XML Schema Documentation

Table of Contents


Schema Document Properties

Target Namespace http://www.w3.org/XML/1998/namespace
Language en
Element and Attribute Namespaces
  • Global element and attribute declarations belong to this schema's target namespace.
  • By default, local element declarations have no namespace.
  • By default, local attribute declarations have no namespace.
Documentation See http://www.w3.org/XML/1998/namespace.html and http://www.w3.org/TR/REC-xml for information about this namespace.

This schema defines attributes and an attribute group suitable for use by schemas wishing to allow xml:base, xml:lang or xml:space attributes on elements they define. To enable this, such a schema must import this schema for the XML namespace, e.g. as follows: <schema . . .> . . . <import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="http://www.w3.org/2001/03/xml.xsd"/> Subsequently, qualified reference to any of the attributes or the group defined below will have the desired effect, e.g. <type . . .> . . . <attributeGroup ref="xml:specialAttrs"/> will define a type which will schema-validate an instance element with any of those attributes

In keeping with the XML Schema WG's standard versioning policy, this schema document will persist at http://www.w3.org/2001/03/xml.xsd. At the date of issue it can also be found at http://www.w3.org/2001/xml.xsd. The schema document at that URI may however change in the future, in order to remain compatible with the latest version of XML Schema itself. In other words, if the XML Schema namespace changes, the version of this document at http://www.w3.org/2001/xml.xsd will change accordingly; the version at http://www.w3.org/2001/03/xml.xsd will not change.

Declared Namespaces

Prefix Namespace
xml http://www.w3.org/XML/1998/namespace
xs http://www.w3.org/2001/XMLSchema
Schema Component Representation
<xs:schema xml:lang="en" targetNamespace="http://www.w3.org/XML/1998/namespace">

Global Declarations

Attribute: base

Name base
Type xs:anyURI
Documentation See http://www.w3.org/TR/xmlbase/ for information about this attribute.
XML Instance Representation
Schema Component Representation
<xs:attribute name="base" type="xs:anyURI"/>

Attribute: lang

Name lang
Type xs:language
Documentation In due course, we should install the relevant ISO 2- and 3-letter codes as the enumerated possible values . . .
XML Instance Representation
Schema Component Representation
<xs:attribute name="lang" type="xs:language"/>

Attribute: space

Name space
Type Locally-defined simple type
Default Value preserve
XML Instance Representation
xml:space="xs:NCName (value comes from list: {'default'|'preserve'})"
Schema Component Representation
<xs:attribute name="space" default="preserve">
<xs:restriction base="xs:NCName">
<xs:enumeration value="default"/>
<xs:enumeration value="preserve"/>

Global Definitions

Attribute Group: specialAttrs

Name specialAttrs
XML Instance Representation
Schema Component Representation
<xs:attributeGroup name="specialAttrs">
<xs:attribute ref="xml:base"/>
<xs:attribute ref="xml:lang"/>
<xs:attribute ref="xml:space"/>


Complex Type:

Schema Component Type


Schema Component Name
Super-types: Address < AusAddress (by extension)
  • QLDAddress (by restriction)
If this schema component is a type definition, its type hierarchy is shown in a gray-bordered box.
Name AusAddress
Abstract no
The table above displays the properties of this schema component.
XML Instance Representation
<... country="Australia">
<unitNo> string </unitNo> [0..1]
<houseNo> string </houseNo> [1]
<street> string </street> [1]
Start Choice[1]
<city> string </city> [1]
<town> string </town> [1]
End Choice
<state> AusStates </state> [1]
<postcode> string <<pattern = [1-9][0-9]{3}>> </postcode> [1]?

The XML Instance Representation table above shows the schema component's content as an XML instance.

Schema Component Representation
<elementname="state" type="AusStates"/>
<attributename="country" type="string" fixed="Australia"/>
The Schema Component Representation table above displays the underlying XML representation of the schema component. (Annotations are not shown.)


Abstract (Applies to complex type definitions and element declarations). An abstract element or complex type cannot used to validate an element instance. If there is a reference to an abstract element, only element declarations that can substitute the abstract element can be used to validate the instance. For references to abstract type definitions, only derived types can be used.

All Model Group Child elements can be provided in any order in instances. See: http://www.w3.org/TR/xmlschema-1/#element-all.

Choice Model Group Only one from the list of child elements and model groups can be provided in instances. See: http://www.w3.org/TR/xmlschema-1/#element-choice.

Collapse Whitespace Policy Replace tab, line feed, and carriage return characters with space character (Unicode character 32). Then, collapse contiguous sequences of space characters into single space character, and remove leading and trailing space characters.

Disallowed Substitutions (Applies to element declarations). If substitution is specified, then substitution group members cannot be used in place of the given element declaration to validate element instances. If derivation methods, e.g. extension, restriction, are specified, then the given element declaration will not validate element instances that have types derived from the element declaration's type using the specified derivation methods. Normally, element instances can override their declaration's type by specifying an xsi:type attribute.

Key Constraint Like Uniqueness Constraint, but additionally requires that the specified value(s) must be provided. See: http://www.w3.org/TR/xmlschema-1/#cIdentity-constraint_Definitions.

Key Reference Constraint Ensures that the specified value(s) must match value(s) from a Key Constraint or Uniqueness Constraint. See: http://www.w3.org/TR/xmlschema-1/#cIdentity-constraint_Definitions.

Model Group Groups together element content, specifying the order in which the element content can occur and the number of times the group of element content may be repeated. See: http://www.w3.org/TR/xmlschema-1/#Model_Groups.

Nillable (Applies to element declarations). If an element declaration is nillable, instances can use the xsi:nil attribute. The xsi:nil attribute is the boolean attribute, nil, from the http://www.w3.org/2001/XMLSchema-instance namespace. If an element instance has an xsi:nil attribute set to true, it can be left empty, even though its element declaration may have required content.

Notation A notation is used to identify the format of a piece of data. Values of elements and attributes that are of type, NOTATION, must come from the names of declared notations. See: http://www.w3.org/TR/xmlschema-1/#cNotation_Declarations.

Preserve Whitespace Policy Preserve whitespaces exactly as they appear in instances.

Prohibited Derivations (Applies to type definitions). Derivation methods that cannot be used to create sub-types from a given type definition.

Prohibited Substitutions (Applies to complex type definitions). Prevents sub-types that have been derived using the specified derivation methods from validating element instances in place of the given type definition.

Replace Whitespace Policy Replace tab, line feed, and carriage return characters with space character (Unicode character 32).

Sequence Model Group Child elements and model groups must be provided in the specified order in instances. See: http://www.w3.org/TR/xmlschema-1/#element-sequence.

Substitution Group Elements that are members of a substitution group can be used wherever the head element of the substitution group is referenced.

Substitution Group Exclusions (Applies to element declarations). Prohibits element declarations from nominating themselves as being able to substitute a given element declaration, if they have types that are derived from the original element's type using the specified derivation methods.

Target Namespace The target namespace identifies the namespace that components in this schema belongs to. If no target namespace is provided, then the schema components do not belong to any namespace.

Uniqueness Constraint Ensures uniqueness of an element/attribute value, or a combination of values, within a specified scope. See: http://www.w3.org/TR/xmlschema-1/#cIdentity-constraint_Definitions.