W3C

XML Schema Part 2: Datatypes

W3C Working Draft 07 April 2000

This version:
http://www.w3.org/TR/2000/WD-xmlschema-2-20000407/
(in XML and HTML, with a schema and DTD including datatype definitions, as well as a schema for built-in datatypes only, in a separate namespace.)
Latest version:
http://www.w3.org/TR/xmlschema-2/
Previous version:
http://www.w3.org/TR/2000/WD-xmlschema-2-20000225/
Editors:
Paul V. Biron (Kaiser Permanente, for Health Level Seven) <Paul.V.Biron@kp.org>
Ashok Malhotra (IBM) <petsa@us.ibm.com>

Copyright ©1999-2000 W3C® (MIT, INRIA, Keio), All Rights Reserved. W3C liability, trademark, document use and software licensing rules apply.


Abstract

XML Schema: Datatypes is part 2 of a two-part draft of the specification for the XML Schema definition language. This document proposes facilities for defining datatypes to be used in XML Schemas and other XML specifications. The datatype language, which is itself represented in XML 1.0, provides a superset of the capabilities found in XML 1.0 document type definitions (DTDs) for specifying datatypes on elements and attributes.

Status of this document

This is the Last-Call public working draft of XML Schema 1.0, issued by the XML Schema Working Group, for review by the public and by members and working groups of the World Wide Web Consortium.

This working draft incorporates all Working Group decisions through 2000-04-06. It has been reviewed by the XML Schema Working Group, and the Working Group has agreed to its publication as a Last Call draft. The Last Call period is expected to end 12 May 2000. Following this Last Call for Review, the Working Group intends to submit this specification for publication as a Candidate Recommendation.

This schedule may vary, depending on the comments of the public and of other W3C working groups on this draft. Such comments are instrumental in the WG's deliberations, and we encourage readers to review the draft and to send comments to www-xml-schema-comments@w3.org. An archive of the comments received is available.

Although the Working Group does not anticipate further changes to the functionality described here, this is still a working draft, subject to change. The present version should be implemented only by those interested in providing a check on its design or by those preparing for an implementation of the Candidate Recommendation. The Schema WG will not allow early implementation to constrain its ability to make changes to this specification prior to final release.

A list of current W3C working drafts can be found at http://www.w3.org/TR/. They may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use W3C Working Drafts as reference material or to cite them as other than "work in progress".

Several "note types" are used throughout this draft:

issue [Issue (issue-name): ]
something on which the editors are seeking comment.
editorial note [Ed. Note: ]
something the editors wish to call to the attention of the reader. To be removed prior to the recommendation becoming final.
note [Note: ]
something the editors wish to call to the attention of the reader. To remain in the final recommendation.

Table of contents

1 Introduction
    1.1 Purpose
    1.2 Requirements
    1.3 Scope
    1.4 Terminology
    1.5 Constraints and Contributions
2 Type System
    2.1 Datatype
    2.2 Value space
    2.3 Lexical space
    2.4 Facets
        2.4.1 Fundamental facets
        2.4.2 Constraining or Non-fundamental facets
    2.5 Datatype dichotomies
        2.5.1 Atomic vs. list datatypes
        2.5.2 Primitive vs. derived datatypes
        2.5.3 Built-in vs. user-derived datatypes
3 Built-in datatypes
    3.1 Namespace considerations
    3.2 Primitive datatypes
        3.2.1 string
        3.2.2 boolean
        3.2.3 float
        3.2.4 double
        3.2.5 decimal
        3.2.6 timeDuration
        3.2.7 recurringDuration
        3.2.8 binary
        3.2.9 uriReference
        3.2.10 ID
        3.2.11 IDREF
        3.2.12 ENTITY
        3.2.13 NOTATION
        3.2.14 QName
    3.3 Derived datatypes
        3.3.1 language
        3.3.2 IDREFS
        3.3.3 ENTITIES
        3.3.4 NMTOKEN
        3.3.5 NMTOKENS
        3.3.6 Name
        3.3.7 NCName
        3.3.8 integer
        3.3.9 nonPositiveInteger
        3.3.10 negativeInteger
        3.3.11 long
        3.3.12 int
        3.3.13 short
        3.3.14 byte
        3.3.15 nonNegativeInteger
        3.3.16 unsignedLong
        3.3.17 unsignedInt
        3.3.18 unsignedShort
        3.3.19 unsignedByte
        3.3.20 positiveInteger
        3.3.21 timeInstant
        3.3.22 time
        3.3.23 timePeriod
        3.3.24 date
        3.3.25 month
        3.3.26 year
        3.3.27 century
        3.3.28 recurringDate
        3.3.29 recurringDay
4 Datatype components
    4.1 Datatype definition
    4.2 Constraining facets
        4.2.1 length
        4.2.2 minLength
        4.2.3 maxLength
        4.2.4 pattern
        4.2.5 enumeration
        4.2.6 maxInclusive
        4.2.7 maxExclusive
        4.2.8 minExclusive
        4.2.9 minInclusive
        4.2.10 precision
        4.2.11 scale
        4.2.12 encoding
        4.2.13 duration
        4.2.14 period
5 XML representation of datatype definitions
    5.1 XML representation of datatype definitions
        5.1.1 Derivation by restriction
        5.1.2 Derivation by list
    5.2 Constraining facets
        5.2.1 length
        5.2.2 minLength
        5.2.3 maxLength
        5.2.4 pattern
        5.2.5 enumeration
        5.2.6 maxInclusive
        5.2.7 maxExclusive
        5.2.8 minInclusive
        5.2.9 minExclusive
        5.2.10 precision
        5.2.11 scale
        5.2.12 encoding
        5.2.13 duration
        5.2.14 period
6 Conformance

Appendices

A Schema for Datatype Definitions (normative)
B DTD for Datatype Definitions (normative)
C Datatypes and Facets
    C.1 Fundamental Facets
    C.2 Constraining Facets
D ISO 8601 Date and Time Formats
    D.1 ISO 8601 Conventions
    D.2 Truncated and Reduced Formats -- Changed Heading for Section
    D.3 Deviations from ISO 8601 Formats
        D.3.1 Sign Allowed
        D.3.2 More Than 9999 Years
E Regular Expressions
    E.1 Character Classes
        E.1.1 Character Class Escapes
F References
    F.1 Normative
    F.2 Non-normative
G Acknowledgments (non-normative)
H Revisions from Previous Draft

1 Introduction

1.1 Purpose

The [XML 1.0 Recommendation] specification defines limited facilities for applying datatypes to document content in that documents may contain or refer to DTDs that assign types to elements and attributes. However, document authors, including authors of traditional documents and those transporting data in XML, often require a higher degree of type checking to ensure robustness in document understanding and data interchange.

The table below offers two typical examples of XML instances in which datatypes are implicit: the instance on the left represents a billing invoice, the instance on the right a memo or perhaps an email message in XML.

Data oriented Document oriented
<invoice>
   <orderDate>1999-01-21</orderDate>
   <shipDate>1999-01-25</shipDate>
   <billingAddress>
      <name>Ashok Malhotra</name>
      <street>123 IBM Ave.</street>
      <city>Hawthorne</city>
      <state>NY</state>
      <zip>10532-0000</zip>
   </billingAddress>
   <voice>555-1234</voice>
   <fax>555-4321</fax>
</invoice>
<memo importance='high'
      date='1999-03-23'>
   <from>Paul V. Biron</from>
   <to>Ashok Malhotra</to>
   <subject>Latest draft</subject>
   <body>
      We need to discuss the latest
      draft <emph>immediately</emph>.
      Either email me at <email>
      mailto:paul.v.biron@kp.org</email>
      or call <phone>555-9876</phone>
   </body>
</memo>

The invoice contains several dates and telephone numbers, the postal abbreviation for a state (which comes from an enumerated list of sanctioned values), and a ZIP code (which takes a definable regular form). The memo contains many of the same types of information: a date, telephone number, email address and an "importance" value (from an enumerated list, such as "low", "medium" or "high"). Applications which process invoices and memos need to raise exceptions if something that was supposed to be a date or telephone number does not conform to the rules for valid dates or telephone numbers.

In both cases, validity constraints exist on the content of the instances that are not expressible in XML DTDs. The limited datatyping facilities in XML have prevented validating XML processors from supplying the rigorous type checking required in these situations. The result has been that individual applications writers have had to implement type checking in an ad hoc manner. This specification addresses the need of both document authors and applications writers for a robust, extensible datatype system for XML which could be incorporated into XML processors. As discussed below, these datatypes could be used in other XML-related standards as well.

1.2 Requirements

The [XML Schema Requirements] document spells out concrete requirements to be fulfilled by this specification, which state that the XML Schema Language must:

  1. provide for primitive data typing, including byte, date, integer, sequence, SQL & Java primitive data types, etc.;
  2. define a type system that is adequate for import/export from database systems (e.g., relational, object, OLAP);
  3. distinguish requirements relating to lexical data representation vs. those governing an underlying information set;
  4. allow creation of user-defined datatypes, such as datatypes that are derived from existing datatypes and which may constrain certain of its properties (e.g., range, precision, length, format).

1.3 Scope

This portion of the XML Schema Language discusses datatypes that can be used in an XML Schema. These datatypes can be specified for element content that would be specified as #PCDATA and attribute values of various types in a DTD. It is the intention of this specification that it be usable outside of the context of XML Schemas for a wide range of other XML-related activities such as [XSL] and [RDF Schema].

1.4 Terminology

The terminology used to describe XML Schema Datatypes is defined in the body of this specification. The terms defined in the following list are used in building those definitions and in describing the actions of a datatype processor:

[Definition:]   for compatibility
A feature of this specification included solely to ensure that schemas which use this feature remain compatible with [XML 1.0 Recommendation]
[Definition:]  may
Conforming documents and processors are permitted to but need not behave as described.
[Definition:]  match
(Of strings or names:) Two strings or names being compared must be character for character the same.
[Definition:]  must
Conforming documents and processors are required to behave as described; otherwise they are in error.
[Definition:]  error
A violation of the rules of this specification; results are undefined. Conforming software may detect and report an error and may recover from it.

1.5 Constraints and Contributions

This specification provides three different kinds of normative statements about schema components, their representations in XML and their contribution to the schema-validation of information items:

[Definition:]   Constraint on Schemas
Constraints on the schema components themselves, i.e. conditions components must satisfy to be components at all. Largely to be found in Datatype components (§4).
[Definition:]   Schema Representation Constraint
Constraints on the representation of schema components in XML. Some but not all of these are expressed in Schema for Datatype Definitions (normative) (§A) and DTD for Datatype Definitions (normative) (§B). Largely to be found in XML representation of datatype definitions (§5).
[Definition:]   Validity Contribution
Constraints expressed by schema components which information items must satisfy to be schema-valid. Largely to be found in Datatype components (§4).

2 Type System

This section describes the conceptual framework behind the type system defined in this specification. The framework has been influenced by the [ISO 11404] standard on language-independent datatypes as well as the datatypes for [SQL] and for programming languages such as Java.

The datatypes discussed in this specification are computer representations of well known abstract concepts such as integer and date. It is not the place of this specification to define these abstract concepts; many other publications provide excellent definitions.

2.1 Datatype

[Definition:]  In this specification, a datatype is a 3-tuple, consisting of a) a set of distinct values, called its value space, b) a set of lexical representations, called its lexical space, and c) a set of facets that characterize properties of the value space, individual values or lexical items.

2.2 Value space

[Definition:]  A value space is the set of values for a given datatype. Each value in the value space of a datatype is denoted by one or more literals in its lexical space.

The value space of a given datatype can be defined in one of the following ways:

value spaces have certain properties. For example, they always have the property of cardinality, some definition of equality and may be ordered by which individual values within the value space can be compared to one another. The properties of value spaces that are recognized by this specification are defined in Fundamental facets (§2.4.1).

2.3 Lexical space

In addition to its value space, each datatype also has a lexical space.

[Definition:]  A lexical space is the set of valid literals for a datatype (literals may appear as one or more character information items as defined in [XML Information Set]).

For example, "100" and "1.0E2" are two different literals from the lexical space of float which both denote the same value. The type system defined in this specification provides a mechanism for schema designers to control the set of values and the corresponding set of acceptable literals of those values for a datatype.

2.4 Facets

[Definition:]  A facet is a single defining aspect of a value space. Generally speaking, each facet characterizes a value space along independent axes or dimensions.

The facets of a datatype serve to distinguish those aspects of one datatype which differ from other datatypes. Rather than being defined solely in terms of a prose description the datatypes in this specification are defined in terms of the synthesis of facet values which together determine the value space and properties of the datatype.

Facets are of two types: fundamental facets that define the datatype and non-fundamental or constraining facets that constrain the permitted values of a datatype.

2.4.1 Fundamental facets

[Definition:]   A fundamental facet is an abstract property which serves to semantically characterize the values of a value space.

These properties are discussed in this section.

2.4.1.1 Equal

Every value space supports the notion of equality, with the following rules:

  • for any two instances of values from the value space (a,b), either a is equal to b, denoted a = b, or a is not equal to b, denoted a != b;
  • there is no pair of instances (a, b) of values from the value space such that both a = b and a != b;
  • for every value a from the value space, a = a;
  • for any two instances (a, b) of values from the value space, a = b if and only if b = a;
  • for any three instances (a, b, c) of values from the value space, if a = b and b = c, then a = c.

On every datatype, the operation Equal is defined in terms of the equality property of the value space: for any values a, b drawn from the value space, Equal(a,b) is true if a = b, and false otherwise.

By definition, given value space A and value space B where A and B are not related by , for every pair of values a from A and b from B, a != b.

2.4.1.2 Order

[Definition:]  An order relation on a value space is a mathematical relation which imposes a total order on the members of the value space.

[Definition:]  A value space, and hence a datatype, is said to be ordered if there exists an order-relation defined for that value space.

order relations have the following rules:

  • for every pair (a, b) from the value space, either a < b or b < a, or a = b;
  • for every triple (a, b, c) from the value space, if a < b and b < c, then a < c.
2.4.1.3 Bounds

[Definition:]   A value space is bounded above if there exists a unique value U in the value space such that, for all values v in the value space, v <= U. [Definition:]   The value U is said to be an upper bound of the value space.

[Definition:]  A value space is bounded below if there exists a unique value L in the space such that, for all values v in the value space, L <= v. [Definition:]   The value L is then said to be a lower bound of the value space.

[Definition:]  A datatype is bounded if its value space has both an upper bound and a lower bound.

2.4.1.4 Cardinality

[Definition:]  Every value space has associated with it the concept of cardinality. Some value spaces are finite, some are countably infinite while still others are uncountably infinite. A datatype is said to have the cardinality of its value space.

It is sometimes useful to categorize value spaces (and hence, datatypes) as to their cardinality, there are two significant cases:

2.4.1.5 Numeric

[Definition:]  A datatype is said to be numeric if its values are conceptually quantities (in some mathematical number system).

[Definition:]  A datatype whose values are not numeric is said to be non-numeric.

2.4.2 Constraining or Non-fundamental facets

[Definition:]  A constraining facet is an optional property that can be applied to a datatype to constrain its value space.

Constraining the value space consequently constrains the lexical space. Adding constraining facets to a base type is described in Derivation by restriction (§5.1.1).

In this section we define all constraining facets that are available for use when defining derived datatypes.

2.4.2.1 length

[Definition:]  length is the number of units of length, where units of length varies depending on the base type. The value of length must be a nonNegativeInteger.

For datatypes derived from string, length is measured in units of [Unicode] code points. For datatypes derived from binary, length is measured in octets (8 bits) of binary data. For datatypes derived by list, length is measured in list items.

2.4.2.2 minLength

[Definition:]  minLength is the minimum number of units of length, where units of length varies depending on the base type. The value of minLength must be a nonNegativeInteger.

For datatypes derived from string, minLength is measured in units of [Unicode] code points. For datatypes derived from binary, minLength is measured in octets (8 bits) of binary data. For datatypes derived by list, length is measured in list items.

2.4.2.3 maxLength

[Definition:]  maxLength is the maximum number of units of length, where units of length varies depending on the base type. The value of maxLength must be a nonNegativeInteger.

For datatypes derived from string, maxLength is measured in units of [Unicode] code points. For datatypes derived from binary, maxLength is measured in octets (8 bits) of binary data. For datatypes derived by list, length is measured in list items.

2.4.2.4 pattern

[Definition:]   pattern is a constraint on the value space of a datatype which is achieved by constraining the lexical space to literals which match a specific pattern. The value of pattern must be a regular expression.

2.4.2.5 enumeration

[Definition:]   enumeration constrains the value space to a specified set of values.

enumeration does not impose an order relation on the value space it creates; the ordered property of the datatype involved remains that of the base type.

2.4.2.6 maxInclusive

[Definition:]   maxInclusive is the upper bound of the value space for a datatype with the ordered property. The value is inclusive in the sense that the value is itself included in the value space. The value of maxInclusive must be of the same type as the base type.

2.4.2.7 maxExclusive

[Definition:]   maxExclusive is the upper bound of the value space for a datatype with the ordered property. The value is exclusive in the sense that the value is itself excluded from the value space. The value of maxExclusive must be of the same type as the base type.

2.4.2.8 minInclusive

[Definition:]   minInclusive is the lower bound of the value space for a datatype with the ordered property. The value is inclusive in the sense that the value is itself included in the value space. The value of minInclusive must be of the same type as the base type.

2.4.2.9 minExclusive

[Definition:]   minExclusive is the lower bound of the value space for a datatype with the ordered property. The value is exclusive in the sense that the value is itself excluded from the value space for the datatype. The value of minExclusive must be of the same type as the base type.

2.4.2.10 precision

[Definition:]  precision is the maximum number of decimal digits in values of datatypes derived from decimal. The value of precision must be a positiveInteger.

2.4.2.11 scale

[Definition:]  scale is the maximum number of decimal digits in the fractional part of values of datatypes derived from decimal. The value of scale must be a nonNegativeInteger .

2.4.2.12 encoding

[Definition:]  encoding is the encoded form of the lexical space of datatypes derived from binary. The value of encoding must be one of {hex, base64}.

If the value of encoding is hex then each binary octect is encoded as a character tuple, consisting the two hexadecimal digits ([0-9a-fA-F]) representing the octet code. For example, "20" is the hex encoding for the US-ASCII space character.

If the value of encoding is base64 then the entire binary stream is encoding using the Base64 Content-Transfer-Encoding defined in Section 6.8 [RFC 2045].

2.4.2.13 duration

[Definition:]  duration is the duration of values for the datatype recurringDuration and datatypes derived from recurringDuration. The value of duration must be a timeDuration.

2.4.2.14 period

[Definition:]  period is the frequency of recurrence for values for the datatype recurringDuration and datatypes derived from recurringDuration. The value of period must be timeDuration.

2.5 Datatype dichotomies

It is useful to categorize the datatypes defined in this specification along various dimensions, forming a set of characterization dichotomies.

2.5.1 Atomic vs. list datatypes

The first distinction to be made is that between atomic and list datatypes.

  • [Definition:]  Atomic datatypes are those having values which are regarded by this specification as being indivisible.
  • [Definition:]  List datatypes are those having values which consist of a finite-length sequence of values of an atomic datatype.

For example, a single token which matches Nmtoken from [XML 1.0 Recommendation] could be the value of an atomic datatype (NMTOKEN); while a sequence of such tokens could be the value of a list datatype (NMTOKENS).

2.5.1.1 Atomic datatypes

atomic datatypes may be either primitive or derived. The value space of an atomic datatype is a set of "atomic" values, which for the purposes of this specification, are not further decomposable. The lexical space of an atomic datatype is a set of literals whose internal structure is specific to the datatype in question.

2.5.1.2 List datatypes

Several type systems (such as the one described in [ISO 11404]) treat list datatypes as special cases of the more general notions of aggregate or collection datatypes.

list datatypes are always derived. The value space of a list datatype is a set of finite-length sequences of atomic values. The lexical space of a list datatype is a set of literals whose internal structure is a whitespace separated sequence of literals of the atomic datatype of the items in the list (where whitespace matches S in [XML 1.0 Recommendation]).

Example
<simpleType name='sizes' base='decimal' derivedBy='list'/>
<cerealSizes xsi:type='sizes'> 8 10.5 12 </cerealSizes>

A list datatype can be derived from an atomic datatype whose lexical space allows whitespace. In such a case, regardless of the input, list items will be separated at whitespace boundaries.

Example
<simpleType name='listOfString' base='string' derivedBy='list'/>
<someElement xsi:type='listOfString'>
this is not list item 1
this is not list item 2
this is not list item 3
</someElement>
In the above example, the value of the someElement element is not a list of length 3; rather, it is a list of length 18.

When a datatype is derived from a list datatype, the following constraining facets may be used:

For each of the above facets, the unit of length is measured in number of list items.

NOTE: A datatype which is atomic in this specification need not be an "atomic" datatype in any programming language used to implement this specification. Likewise, a datatype which is a list in this specification need not be a "list" datatype in any programming language used to implement this specification.

2.5.2 Primitive vs. derived datatypes

Next, we distinquish between primitive and derived datatypes.

  • [Definition:]  Primitive datatypes are those that are not defined in terms of other datatypes; they exist ab initio.
  • [Definition:]  Derived datatypes are those that are defined in terms of other datatypes.

For example, a float is a well-defined mathematical concept that cannot be defined in terms of other datatypes while a date is a special case of the more general datatype recurringDuration.

The datatypes defined by this specification fall into both the primitive and derived categories. It is felt that a judiciously chosen set of primitive datatypes will serve the widest possible audience by providing a set of convenient datatypes that can be used as is, as well as providing a rich enough base from which the variety of datatypes needed by schema designers can be derived.

[Definition:]  Every derived datatype is defined in terms of an existing datatype, referred to as the base type. base types may be either primitive or derived.

In the example above, date is derived from the base type recurringDuration.

NOTE: A datatype which is primitive in this specification need not be a "primitive" datatype in any programming language used to implement this specification. Likewise, a datatype which is derived in this specification need not be a "derived" datatype in any programming language used to implement this specification.

2.5.3 Built-in vs. user-derived datatypes

Conceptually there is no difference between the built-in derived datatypes included in this specification and the user-derived datatypes which will be created by individual schema designers. The built-in derived datatypes are those which are believed to be so common that if they were not defined in this specification many schema designers would end up "reinventing" them. Furthermore, including these derived datatypes in this specification serves to demonstrate the mechanics and utility of the datatype generation facilities of this specification.

NOTE: A datatype which is built-in in this specification need not be a "built-in" datatype in any programming language used to implement this specification. Likewise, a datatype which is user-derived in this specification need not be a "user-derived" datatype in any programming language used to implement this specification.

3 Built-in datatypes

3.1 Namespace considerations

The built-in datatypes defined by this specification are designed so that systems other than the XML Schema definition language may use them. To facilitate such usage the built-in datatypes in this specification have the namespace URI:

This applies to both built-in primitive and built-in derived datatypes.

Each user-derived datatype is also associated with a unique namespace. However, user-derived datatypes do not come from the namespace defined by this specification; rather, they come from the namespace of the schema in which they are defined (see XML Representation of Schemas in [XML Schema Part 1: Structures]).

As described in more detail in XML representation of datatype definitions (§5.1), each user-derived datatype must be defined in terms of another datatype in one of two ways: 1) by assigning constraining facets which serve to restrict the value space of the user-derived datatype to a subset of the base type; 2) by creating a list datatype whose value space consists of finite-length sequences of values of the base type.

3.2 Primitive datatypes

The primitive datatypes defined by this specification are described below. For each datatype, the value space and lexical space are defined, all constraining facets which apply to the datatype are given and any datatypes derived from this the datatype are specified.

primitive datatypes can only be added by revisions to this specification.

3.2.1 string

[Definition:]  The string datatype represents character strings in XML. The value space of string is the set of finite-length sequences of UCS characters ([ISO 10646] and [Unicode]). A UCS character (or just character, for short) is an atomic unit of communication; it is not further specified except to note that every UCS character has a corresponding UCS code point, which is an integer. The order-relation of string is the lexicographic ordering by [Unicode] code point.

3.2.1.2 Derived datatypes

string has the following built-in  derived datatypes:

3.2.2 boolean

[Definition:]  boolean has the value space required to support the mathematical concept of binary-valued logic: {true, false}.

3.2.2.1 Lexical Representation

An instance of a datatype that is defined as boolean can have the following legal lexical values {true, 1, false, 0}, with '1' being the same as 'true' and '0' being the same as 'false'.

3.2.2.2 Constraining facets

boolean has the following constraining facets:

3.2.3 float

[Definition:]  float corresponds to the IEEE single-precision 32-bit floating point type [IEEE 754-1985]. The basic value space of float consists of the values m × 2^e, where m is an integer whose absolute value is less than 2^24, and e is an integer between -149 and 104, inclusive. In addition to the basic value space described above, the value space of float also contains the following special values: positive and negative zero, positive negative infinity and not-a-number. The order-relation on float is: x < y iff y - x is positive.

A literal in the lexical space representing a decimal number d maps to the normalized value in the value space of float that is closest to d; if d is exactly halfway between two such values then the even value is chosen. This is the best approximation of d [Clinger, WD (1990)] [Gay, DM (1990)], which is more accurate than the mapping required by [IEEE 754-1985].

3.2.3.1 Lexical representation

float values have a lexical representation consisting of a mantissa followed, optionally, by the character "E" or "e", followed by an exponent. The exponent must be an integer. The mantissa must be a decimal number. The representations for exponent and mantissa must follow the lexical rules for integer and decimal. If the "E" or "e" and the following exponent are omitted, an exponent value of 0 is assumed.

The special values positive and negative zero, positive and negative infinity and not-a-number have 0, -0, INF, -INF and NaN, respectively.

For example, -1E4, 1267.43233E12, 12.78e-2, 12 and INF are all legal literals for float.

3.2.3.2 Constraining facets

float has the following constraining facets:

3.2.4 double

[Definition:]  The double datatype corresponds to IEEE double-precision 64-bit floating point type [IEEE 754-1985]. The basic value space of double consists of the values m × 2^e, where m is an integer whose absolute value is less than 2^53, and e is an integer between -1075 and 970, inclusive. In addition to the basic value space described above, the value space of double also contains the following special values: positive and negative zero, positive negative infinity and not-a-number. The order-relation on double is: x < y iff y - x is positive.

A literal in the lexical space representing a decimal number d maps to the normalized value in the value space of double that is closest to d; if d is exactly halfway between two such values then the even value is chosen. This is the best approximation of d ([Clinger, WD (1990)], [Gay, DM (1990)]), which is more accurate than the mapping required by [IEEE 754-1985].

3.2.4.1 Lexical representation

double values have a lexical representation consisting of a mantissa followed, optionally, by the character "E" or "e", followed by an exponent. The exponent must be an integer. The mantissa must be a decimal number. The representations for exponent and mantissa must follow the lexical rules for integer and decimal. If the "E" or "e" and the following exponent are omitted, an exponent value of 0 is assumed.

The special values positive and negative zero, positive and negative infinity and not-a-number have 0, -0, INF, -INF and NaN, respectively.

For example, -1E4, 1267.43233E12, 12.78e-2, 12 and INF are all legal literals for double.

3.2.4.2 Constraining facets

double has the following constraining facets:

3.2.5 decimal

[Definition:]  decimal represents arbitrary precision decimal numbers. The value space of decimal consists of the values i × 10^n, where i and n are integers, with n being known as the scale of the value space. The order-relation on decimal is: x < y iff y - x is positive.

NOTE: The use of arbitrary precision decimal numbers, including all datatypes derived from decimal (e.g., integer) in this design impacts the implementation of schema processors in a number of places: checking maxLength constraints on strings, for example. It may impact interchange between XML schemas and programming languages, databases, etc.

Our design discussions did not reveal convincing evidence of undue burden because of arbitrary precision decimal numbers in this design, but we welcome further input from implementors.
3.2.5.1 Lexical representation

decimal has a lexical representation consisting of a finite-length sequence of decimal digits separated by a period as a decimal indicator, in accordance with the scale and precision facets, with an optional leading sign. If the sign is omitted, "+" is assumed. Leading and trailing zeroes are optional. If the fractional part is zero, the period and following zero(es) can be omitted. For example: -1.23, 12678967.543233, +100000.00.

3.2.5.3 Derived datatypes

decimal has the following built-in  derived datatypes:

3.2.6 timeDuration

[Definition:]   timeDuration represents a duration of time. The value space of timeDuration is the space of time durations as defined in § 5.5.3.2 of [ISO 8601]. The order-relation on timeDuration is: x < y iff y - x is positive.

3.2.6.1 Lexical Representation

A single lexical representation, conforming to a subset of the representations allowed by [ISO 8601], is allowed for timeDuration. This lexical representation is the [ISO 8601] extended format PnYn MnDTnH nMnS, where nY represents the number of years, nM the number of months, nD the number of days, 'T' is the date/time separator, nH the number of hours, nM the number of minutes and nS the number of seconds. The number of seconds can include decimal digits to arbitrary precision. An optional preceding minus sign ('-') is allowed, to indicate a negative duration. If the sign is omitted a positive duration is indicated. See also ISO 8601 Date and Time Formats (§D).

For example, to indicate a duration of 1 year, 2 months, 3 days, 10 hours, and 30 minutes, one would write: P1Y2M3DT10H30M.

Reduced precision and truncated representations of this format are allowed provided they conform to the following:

  • The lowest order items may be omitted. If omitted their value is assumed to be zero.
  • The lowest order item may have a decimal fraction.
  • If the number of years, months, days, hours, minutes, or seconds in any expression equals zero, the number and its corresponding designator may be omitted. However, at least one number and its designator must be present.
  • The designator 'T' shall be absent if all of the time items are absent. The designator 'P' must always be present.

For example, P1347Y, P1347M are P1Y2MT2H are all allowed; P0Y1347M and P0Y1347M0D are allowed. P-1347M is not allowed although -P1347M is allowed. P1Y2MT is not allowed.

3.2.6.2 Constraining facets

timeDuration has the following constraining facets:

3.2.7 recurringDuration

[Definition:]   recurringDuration represents a timeDuration that recurs with a specific timeDuration starting from a specific origin. The order-relation on timeDuration is: x < y iff y - x is positive.

Recurring duration has two constraining facets duration and period whose values must be specified when the datatype is defined. These facets specify the length of the duration and after what duration it recurs. The lexical format used to specify these facet values is the lexical format for timeDuration. A value of 0 for the facet period means that the duration does not recur i.e. there is but a single ocurrence. A value of 0 for the facet duration means that the duration is, in fact, a single instant of time.

Although the primary purpose of this datatype is to serve as a basetype from which the other date and time datatypes are generated, it can be used as a datatype on its own by specifying the values for duration and period when then datatype is defined. The value that appears in an instance document is the value of the origin when the recurrence begins.

Constraint: duration and period required for recurringDuration
It is an error for recurringDuration to be used directly in a schema. Only datatypes that are derived from recurringDuration by specifying a value for duration and period can be used in a schema.
3.2.7.1 Lexical Representation

A single lexical representation, which is a subset of the lexical representations allowed by [ISO 8601], is allowed for recurringDuration. This lexical representation is the [ISO 8601] extended format CCYY-MM-DDThh:mm:ss.sss where "CC" represents the century, "YY" the year, "MM" the month and "DD" the day, preceded by an optional leading sign to indicate a negative number. If the sign is omitted, "+" is assumed. The letter "T" is the date/time separator and "hh", "mm", "ss.sss" represent hour, minute and second respectively. Additional digits can be used to increase the precision of fractional seconds if desired. To accommodate year values greater than 9999 additional digits can be added to the left of this representation.

This representation can be immediately followed by a "Z" to indicate Coordinated Universal Time. To indicate the time zone, i.e. the difference between the local time and Coordinated Universal Time, the difference immediately follows the time and consists of a sign, + or -, followed by hh:mm. See also ISO 8601 Date and Time Formats (§D).

The derived datatype timeInstant uses the same lexical representation. Other derived datatypes date, time, timePeriod and recurringDate use truncated versions of this lexical representation.

3.2.7.2 Constraining facets

recurringDuration has the following constraining facets:

3.2.7.3 Derived datatypes

recurringDuration has the following built-in  derived datatypes:

3.2.8 binary

[Definition:]  binary represents arbitrary binary data. The value space of binary is the set of finite-length sequences of binary octets.

Constraint: encoding required for binary
It is an error for binary to be used directly in a schema. Only datatypes that are derived from binary by minimally specifying a value for encoding can be used in a schema.
3.2.8.1 Constraining facets

binary has the following constraining facets:

Ed. Note: What does the pattern facet on binary really mean? Since pattern operates on the lexical space, one would have to give a regex for the base64 or hex that would result for a specific binary sequence that one wanted to constrain...this is not too far fetched for hex, but almost impossible for base64, isn't it?

3.2.9 uriReference

[Definition:]   uriReference represents a Uniform Resource Identifier (URI) Reference as defined in Section 4 of [RFC 2396]. A uriReference may be absolute or relative, and may have an optional fragment identifier.

[Definition:]   An absolute uriReference refers to a resource in a manner which is independent of the context in which the uriReference occurs.

[Definition:]   A relative uriReference refers to a resource by describing the difference within a hierarchy of resources between the context in which the relative uriReference occurs and the absolute uriReference of the resource.

3.2.9.1 Lexical representation

The lexical space of uriReference is the set of strings that match the URI-reference production in Section 4 of [RFC 2396].

3.2.9.2 Constraining facets

uriReference has the following constraining facets:

3.2.10 ID

[Definition:]  ID represents the ID attribute type from [XML 1.0 Recommendation]. The value space of ID is the set of all strings that match the NCName production in [Namespaces in XML] and have been used in an XML document. The lexical space of ID is the set of all strings that match the NCName production in [Namespaces in XML].

NOTE: The value space of ID is scoped to a specific instance document.

For compatibility (see Terminology (§1.4)) ID should be used only on attributes.

Constraint: ID Unique
An ID must not appear more than once in an XML document as a value of this type; i.e., ID values must uniquely identify the elements which bear them.

3.2.11 IDREF

[Definition:]  IDREF represents the IDREF attribute type from [XML 1.0 Recommendation]. The value space of IDREF is the set of all strings that match the NCName production in [Namespaces in XML] and have been used in an XML document as the value of an element or attribute of type ID. The lexical space of IDREF is the set of strings that match the NCName production in [Namespaces in XML].

NOTE: The value space of IDREF is scoped to a specific instance document.

For compatibility (see Terminology (§1.4)) this datatype should be used only on attributes.

Constraint: IDREF
An IDREF must match the value of an ID in the XML document in which it occurs.
3.2.11.2 Derived datatypes

IDREF has the following built-in  derived datatypes:

3.2.12 ENTITY

[Definition:]  ENTITY represents the ENTITY attribute type from [XML 1.0 Recommendation]. The value space of ENTITY is the set of all strings that match the NCName production in [Namespaces in XML] and have been declared as an unparsed entity in a document type definition. The lexical space of ENTITY is the set of all strings that match the NCName production in [Namespaces in XML].

NOTE: The value space of ENTITY is scoped to a specific instance document.
Constraint: ENTITY declared
ENTITY values must match an unparsed entity name that is declared in the schema.

For compatibility (see Terminology (§1.4)) ENTITY should be used only on attributes.

3.2.12.2 Derived datatypes

ENTITY has the following built-in  derived datatypes:

3.2.13 NOTATION

[Definition:]  NOTATION represents the NOTATION attribute type from [XML 1.0 Recommendation]. The value space of NOTATION is the set of all notations declared in a schema. The lexical space of NOTATION is the set of all strings that match the NCName production in [Namespaces in XML].

NOTE: The value space of NOTATION is scoped to a specific instance document.
Constraint: NOTATION declared
NOTATION values must match a notation name that is declared in the schema.

For compatibility (see Terminology (§1.4)) NOTATION should be used only on attributes.

3.2.14 QName

[Definition:]  QName represents XML qualified names. The value space of QName is the set of tuples {namespace name, local part}, where namespace name is a uriReference and local part is an NCName. The lexical space of QName is the set of strings that match the QName production of [Namespaces in XML].

3.3 Derived datatypes

This section gives conceptual definitions for all built-in derived datatypes defined by this specification. The XML Representation used to define derived datatypes (whether built-in or user-derived) is given in section XML representation of datatype definitions (§5.1) and the complete definitions of the built-in derived datatypes are provided in Appendix Schema for Datatype Definitions (normative) (§A).

3.3.1 language

[Definition:]  language represents natural language identifiers as defined by [RFC 1766]. The value space of language is the set of all strings that match the LanguageID production in [XML 1.0 Recommendation]. The lexical space of language is the set of all strings that match the LanguageID production in [XML 1.0 Recommendation]. The base type of language is string.

3.3.2 IDREFS

[Definition:]  IDREFS represents the IDREFS attribute type from [XML 1.0 Recommendation]. The value space of IDREFS is the set of finite-length sequences of IDREFs that have been used in an XML document. The lexical space of IDREFS is the set of whitespace separated tokens, each of which is in the lexical space of IDREF. The base type of IDREFS is IDREF.

NOTE: The value space of IDREFS is scoped to a specific instance document.

For compatibility (see Terminology (§1.4)) IDREFS should be used only on attributes.

3.3.2.1 Constraining facets

IDREFS has the following constraining facets:

3.3.3 ENTITIES

[Definition:]  ENTITIES represents the ENTITIES attribute type from [XML 1.0 Recommendation]. The value space of ENTITIES is the set of finite-length sequences of ENTITYs that have been declared as unparsed entities in a document type definition. The lexical space of ENTITIES is the set of whitespace separated tokens, each of which is in the lexical space of NMTOKEN. The base type of ENTITIES is ENTITY.

NOTE: The value space of ENTITIES is scoped to a specific instance document.

For compatibility (see Terminology (§1.4)) ENTITIES should be used only on attributes.

3.3.3.1 Constraining facets

ENTITIES has the following constraining facets:

3.3.4 NMTOKEN

[Definition:]  NMTOKEN represents the NMTOKEN attribute type from [XML 1.0 Recommendation]. The value space of NMTOKEN is the set of tokens that match the Nmtoken production in [XML 1.0 Recommendation]. The lexical space of NMTOKEN is the set of strings that match the Nmtoken production in [XML 1.0 Recommendation]. The base type of NMTOKEN is string.

For compatibility (see Terminology (§1.4)) NMTOKEN should be used only on attributes.

3.3.4.2 Derived datatypes

NMTOKEN has the following built-in  derived datatypes:

3.3.5 NMTOKENS

[Definition:]  NMTOKENS represents the NMTOKENS attribute type from [XML 1.0 Recommendation]. The value space of NMTOKENS is the set of fininte-length sequences of NMTOKENs. The lexical space of NMTOKENS is the set of whitespace separated tokens, each of which is in the lexical space of NMTOKEN. The base type of NMTOKENS is NMTOKEN.

For compatibility (see Terminology (§1.4)) NMTOKENS should be used only on attributes.

3.3.5.1 Constraining facets

NMTOKENS has the following constraining facets:

3.3.6 Name

[Definition:]  Name represents XML Names. The value space of Name the set of all strings which match the Name production of [XML 1.0 Recommendation]. The lexical space of Name is the set of all strings which match the Name production of [XML 1.0 Recommendation]. The base type of Name is string.

3.3.6.2 Derived datatypes

Name has the following built-in  derived datatypes:

3.3.7 NCName

[Definition:]  NCName represents XML "non-colonized" Names. The value space of NCName is the set of all strings which match the NCName production of [Namespaces in XML]. The lexical space of NCName is the set of all strings which match the NCName production of [Namespaces in XML]. The base type of NCName is Name.

3.3.8 integer

[Definition:]  integer is derived from decimal by fixing the value of scale to be 0. This results in the standard mathematical concept of the integer numbers. The value space of integer is the infinite set {...,-2,-1,0,1,2,...}. The base type of integer is decimal.

3.3.8.1 Lexical representation

integer has a lexical consisting of a finite-length sequence of decimal digits with an optional leading sign. If the sign is omitted, "+" is assumed. For example: -1, 0, 12678967543233, +100000.

3.3.8.3 Derived datatypes

integer has the following built-in  derived datatypes:

3.3.9 nonPositiveInteger

[Definition:]   nonPositiveInteger is derived from integer by fixing the value of maxInclusive to be 0. This results in the standard mathematical concept of the non-positive integers. The value space of nonPositiveInteger is the infinite set {...,-2,-1,0}. The base type of nonPositiveInteger is integer.

3.3.9.1 Lexical representation

nonPositiveInteger has a lexical representation consisting of a negative sign ("-") followed by a finite-length sequence of decimal digits. If the sequence of digits consists of all zeros then the sign is optional. For example: -1, 0, -12678967543233, -100000.

3.3.9.2 Constraining facets

nonPositiveInteger has the following constraining facets:

3.3.9.3 Derived datatypes

nonPositiveInteger has the following built-in  derived datatypes:

3.3.10 negativeInteger

[Definition:]   negativeInteger is derived from nonPositiveInteger by fixing the value of maxInclusive to be -1. This results in the standard mathematical concept of the negative integers. The value space of negativeInteger is the infinite set {...,-2,-1}. The base type of negativeInteger is nonPositiveInteger.

3.3.10.1 Lexical representation

negativeInteger has a lexical representation consisting of a negative sign ("-") followed by a finite-length sequence of decimal digits. For example: -1, -12678967543233, -100000.

3.3.10.2 Constraining facets

negativeInteger has the following constraining facets:

3.3.11 long

[Definition:]  long is derived from integer by fixing the values of maxInclusive to be 9223372036854775807 and minInclusive to be -9223372036854775808. The base type of long is integer.

3.3.11.1 Lexical representation

long has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits. If the sign is omitted, "+" is assumed. For example: -1, 0, 12678967543233, +100000.

3.3.11.3 Derived datatypes

long has the following built-in  derived datatypes:

3.3.12 int

[Definition:]  int is derived from long by fixing the values of maxInclusive to be 2147483647 and minInclusive to be -2147483648. The base type of int is long.

3.3.12.1 Lexical representation

int has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits. If the sign is omitted, "+" is assumed. For example: -1, 0, 126789675, +100000.

3.3.12.3 Derived datatypes

int has the following built-in  derived datatypes:

3.3.13 short

[Definition:]  short is derived from int by fixing the values of maxInclusive to be 32767 and minInclusive to be -32768. The base type of short is int.

3.3.13.1 Lexical representation

short has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits. If the sign is omitted, "+" is assumed. For example: -1, 0, 12678, +10000.

3.3.13.3 Derived datatypes

short has the following built-in  derived datatypes:

3.3.14 byte

[Definition:]  byte is derived from short by fixing the values of maxInclusive to be 127 and minInclusive to be -128. The base type of byte is short.

3.3.14.1 Lexical representation

byte has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits. If the sign is omitted, "+" is assumed. For example: -1, 0, 126, +100.

3.3.15 nonNegativeInteger

[Definition:]   nonNegativeInteger is derived from integer by fixing the value of minInclusive to be 0. This results in is the standard mathematical concept of the non-negative integers. The value space of nonNegativeInteger is the infinite set {0,1,2,...}. The base type of nonNegativeInteger is integer.

3.3.15.1 Lexical representation

nonNegativeInteger has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits. If the sign is omitted, "+" is assumed. For example: 1, 0, 12678967543233, +100000.

3.3.15.2 Constraining facets

nonNegativeInteger has the following constraining facets:

3.3.15.3 Derived datatypes

nonNegativeInteger has the following built-in  derived datatypes:

3.3.16 unsignedLong

[Definition:]   unsignedLong is derived from nonNegativeInteger by fixing the values of maxInclusive to be 18446744073709551615. The base type of unsignedLong is nonNegativeInteger.

3.3.16.1 Lexical representation

unsignedLong has a lexical representation consisting of a finite-length sequence of decimal digits. For example: 0, 12678967543233, 100000.

3.3.16.2 Constraining facets

unsignedLong has the following constraining facets:

3.3.16.3 Derived datatypes

unsignedLong has the following built-in  derived datatypes:

3.3.17 unsignedInt

[Definition:]   unsignedInt is derived from unsignedLong by fixing the values of maxInclusive to be 4294967295. The base type of unsignedInt is unsignedLong.

3.3.17.1 Lexical representation

unsignedInt has a lexical representation consisting of a finite-length sequence of decimal digits. For example: 0, 1267896754, 100000.

3.3.17.2 Constraining facets

unsignedInt has the following constraining facets:

3.3.17.3 Derived datatypes

unsignedInt has the following built-in  derived datatypes:

3.3.18 unsignedShort

[Definition:]   unsignedShort is derived from unsignedInt by fixing the value maxInclusive to be 65535. The base type of unsignedShort is unsignedInt.

3.3.18.1 Lexical representation

unsignedShort has a lexical representation consisting of a finite-length sequence of decimal digits. For example: 0, 12678, 10000.

3.3.18.2 Constraining facets

unsignedShort has the following constraining facets:

3.3.18.3 Derived datatypes

unsignedShort has the following built-in  derived datatypes:

3.3.19 unsignedByte

[Definition:]   unsignedByte is derived from unsignedShort by fixing the value maxInclusive to be 255. The base type of unsignedByte is unsignedShort.

3.3.19.1 Lexical representation

unsignedByte has a lexical representation consisting of a finite-length sequence of decimal digits. For example: 0, 126, 100.

3.3.19.2 Constraining facets

unsignedByte has the following constraining facets:

3.3.20 positiveInteger

[Definition:]   positiveInteger is derived from nonNegativeInteger by fixing the value of minInclusive to be 1. This results in the standard mathematical concept of the positive integer numbers. The value space of positiveInteger is the infinite set {1,2,...}. The base type of positiveInteger is nonNegativeInteger.

3.3.20.1 Lexical representation

positiveInteger has a lexical representation consisting of an optional positive sign ("+") followed by a finite-length sequence of decimal digits. For example: 1, 12678967543233, +100000.

3.3.20.2 Constraining facets

positiveInteger has the following constraining facets:

3.3.21 timeInstant

[Definition:]   timeInstant represents a specific instant of time. The value space of timeInstant is the space of Combinations of date and time of day values as defined in § 5.4 of [ISO 8601]. The base type of timeInstant is recurringDuration. timeInstant is generated from recurringDuration by setting the value of the duration facet equal to "P0Y" and the value of the period facet equal to "P0Y" (no recurrence).

3.3.21.1 Lexical Representation

A single lexical representation, which is a subset of the lexical representations allowed by [ISO 8601], and is the same lexical representation as its basetype recurringDuration is allowed for timeInstant.

For example, to indicate 1:20 pm on May the 31st, 1999 for Eastern Standard Time which is 5 hours behind Coordinated Universal Time, one would write: 1999-05-31T13:20:00-05:00.

3.3.21.2 Constraining facets

timeInstant has the following constraining facets:

3.3.22 time

[Definition:]  time represents an instant of time that recurs every day. The value space of time is the space of time of day values as defined in § 5.3 of [ISO 8601]. The base type of time is recurringDuration. date is generated from recurringDuration by setting the value of the duration facet equal to "P0Y" and the value of the period facet equal to "PY24H" (24 hours).

3.3.22.1 Lexical Representation

The lexical representation for time is the left truncated lexical representation for timeInstant: hh:mm:ss.sss with optional following time zone indicator. For example, to indicate 1:20 pm for Eastern Standard Time which is 5 hours behind Coordinated Universal Time, one would write: 13:20:00-05:00. See also ISO 8601 Date and Time Formats (§D).

3.3.23 timePeriod

[Definition:]  timePeriod represents a specific period of time with a given start and end. The value space of timePeriod is the value space of Periods of time as defined in § 5.5 of [ISO 8601]. The base type of timePeriod is recurringDuration. timePeriod is generated from recurringDuration by setting the value of the period facet equal to "P0Y" (no recurrence).

The value in the instance specifies the start of the time period while the value of duration facet, specified when subtypes are defined, gives the duration of the time period.

3.3.23.1 Lexical Representation

The lexical representation for timePeriod is the same as that of its basetype, recurringDuration.

3.3.23.2 Constraining facets

timePeriod has the following constraining facets:

Constraint: period facet value required for timePeriod
It is an error for timePeriod to be used directly in a schema. Only datatypes that are derived from timePeriod by specifying a value for duration can be used in a schema.
3.3.23.3 Derived datatypes

timePeriod has the following built-in  derived datatypes:

3.3.24 date

[Definition:]  date represents a timePeriod that starts at midnight of a specified day and lasts for 24 hours. The value space of date is the set of Gregorian calendar dates as defined in § 5.2.1 of [ISO 8601]. The base type of date is timePeriod. date is generated from timePeriod by setting the value of the duration facet equal to "PT24H" (24 hours).

3.3.24.1 Lexical Representation

The lexical representation for date is the reduced (right truncated) lexical representation for timePeriod: CCYY-MM-DD. No left truncation is allowed. An optional following time zone qualifier is allowed as for timePeriod. To accommodate year values outside the range from 0 to 9999, additional digits can be added to the left of this representation and an preceding "-" is allowed.

For example, to indicate May the 31st, 1999, one would write: 1999-05-31. See also ISO 8601 Date and Time Formats (§D).

3.3.25 month

[Definition:]  month represents a timePeriod that starts at midnight on the first day of the month and lasts until the midnight that ends the last day of the month. The value space of date is the set of Gregorian calendar months as defined in § 5.2.1 of [ISO 8601]. The base type of month is timePeriod. month is generated from timePeriod by setting the value of the duration facet equal to "P1M" (the number of days in the specified month).

3.3.25.1 Lexical Representation

The lexical representation for month is the reduced (right truncated) lexical representation for timePeriod: CCYY-MM. No left truncation is allowed. An optional following time zone qualifier is allowed as for timePeriod. To accommodate year values outside the range from 0 to 9999, additional digits can be added to the left of this representation and an preceding "-" is allowed.

For example, to indicate the month of May 1999, one would write: 1999-05. See also ISO 8601 Date and Time Formats (§D).

3.3.26 year

[Definition:]  year represents a timePeriod that starts at the midnight that starts the first day of the year and ends at the midnight that ends the last day of the year. The value space of year is the set of Gregorian calendar years as defined in § 5.2.1 of [ISO 8601]. The base type of year is timePeriod. year is generated from timePeriod by setting the value of the duration facet equal to "P1Y" (the time duration of the specified year).

3.3.26.1 Lexical Representation

The lexical representation for year is the reduced (right truncated) lexical representation for timePeriod: CCYY. No left truncation is allowed. An optional following time zone qualifier is allowed as for timePeriod. To accommodate year values outside the range from 0 to 9999, additional digits can be added to the left of this representation and an preceding "-" is allowed.

For example, to indicate 1999, one would write: 1999. See also ISO 8601 Date and Time Formats (§D).

3.3.27 century

[Definition:]  century represents a timePeriod that starts at the midnight that starts the first day of the century and ends at the midnight that ends that last day of the century. The value space of century is the set of Gregorian calendar centuries as defined in § 5.2.1 of [ISO 8601]. The base type of century is timePeriod. century is generated from timePeriod by setting the value of the duration facet equal to "P100Y" (the duration of the specified century).

3.3.27.1 Lexical Representation

The lexical representation for century is the reduced (right truncated) lexical representation for timePeriod: CC. No left truncation is allowed. An optional following time zone qualifier is allowed as for timePeriod. To accommodate year values outside the range from 0 to 9999, additional digits can be added to the left of this representation and an preceding "-" is allowed.

For example, to indicate the 20th century, one would write: 19. See also ISO 8601 Date and Time Formats (§D).

3.3.27.2 Constraining facets

century has the following constraining facets:

3.3.28 recurringDate

[Definition:]   recurringDate is a date that recurs, specifically a day of the year such as the third of May. Arbitrary recurring dates are not supported by this datatype. The value space of recurringDate is the set of calendar dates, as defined in § 3 of [ISO 8601]. The base type of recurringDate is recurringDuration. recurringDate is generated from recurringDuration by setting the value of the duration facet equal to "PT24H" (24 hours) and the value of the period facet to "P1Y" (one year).

3.3.28.1 Lexical Representation

The lexical representation for recurringDate is the left truncated lexical representation for date: --MM-DD. No other formats are allowed. See also ISO 8601 Date and Time Formats (§D).

3.3.28.2 Constraining facets

recurringDate has the following constraining facets:

3.3.29 recurringDay

[Definition:]   recurringDay is a day that recurs, specifically a day of the month such as the 5th of the month. Arbitrary recurring days are not supported by this datatype. The value space of recurringDay is the space of a set of calendar dates as defined in § 3 of [ISO 8601]. The base type of recurringDay is recurringDuration. recurringDay is generated from recurringDuration by setting the value of the duration facet equal to "PT24H" (24 hours) and the value of the period facet to "P1M" (one month).

3.3.29.1 Lexical Representation

The lexical representation for recurringDay is the left truncated lexical representation for date: ---DD . No other formats are allowed. See also ISO 8601 Date and Time Formats (§D).

3.3.29.2 Constraining facets

recurringDay has the following constraining facets:

4 Datatype components

The following sections provide full details on the properties and significance of each kind of schema component involved in datatype definitions. For each property, the kinds of values it may have is specified. Any property not identified as optional is required to be present, optional properties which are absent are taken to have the null value.

Throughout the following sections, the [value] of an attribute information item means a string composed of, in order, the [character code] of each character information item in the [children] of that attribute information item.

For more information on the notion of datatype (schema) components, see Schema Component Details

NOTE: Readers whose primary interest is in the XML representation of datatype definitions may wish to skip this section on the first reading, concentrating instead on XML representation of datatype definitions (§5).

4.1 Datatype definition

Datatype definitions provide for:

The datatype definition schema component has the following properties:

Schema ComponentDatatype Definition
[name]
Optional. An NCName as defined by [Namespaces in XML].
[base type definition]
A datatype definition.
[facets]
A possibly empty set of Constraining facets (§4.2).
[fundamental facets]
A set of Fundamental facets (§2.4.1)
[variety]
One of {atomic, list}.
[target namespace]
Either null or a namespace URI, as defined in [Namespaces in XML].
[annotation]
Optional. An annotation.

Datatypes are identified by their {name} and {target namespace}. Except for anonymous datatypes (those with no {name}), datatype definitions must be uniquely identified within an schema.

If {variety} is atomic then the value space of the datatype defined will be a subset of the value space of {base type definition}. If {variety} is list then the value space of the datatype defined will be a finite-length sequence of values from the value space of {base type definition}.

The value of {facets} consists of the set of facets specified directly in the datatype definition unioned with the possibly empty set of {facets} of {base type definition}.

The value of {fundamental facets} consists of the set of fundamental facets and their values.

Constraint on Schemas: applicable facets
The constraining facets which are allowed the be members of {facets} are dependent on {base type definition} as specified in the following table:
 {base type definition}applicable {facets}
If {variety} is list, then
 [all datatypes]length, minLength, maxLength, enumeration
else if {variety} is atomic, then
primitivestringlength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
booleanpattern
floatpattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
doublepattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
decimalprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
timeDurationpattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
recurringDurationduration, period, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
binaryencoding, length, minLength, maxLength, pattern, enumeration
uriReferencelength, minLength, maxLength, pattern, enumeration
IDlength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
IDREFlength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
ENTITYlength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
NOTATIONlength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
QNamelength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
derivedlanguagelength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
IDREFSlength, minLength, maxLength, enumeration
ENTITIESlength, minLength, maxLength, enumeration
NMTOKENlength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
NMTOKENSlength, minLength, maxLength, enumeration
Namelength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
NCNamelength, minLength, maxLength, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
integerprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
nonPositiveIntegerprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
negativeIntegerprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
longprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
intprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
shortprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
byteprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
nonNegativeIntegerprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
unsignedLongprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
unsignedIntprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
unsignedShortprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
unsignedByteprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
positiveIntegerprecision, scale, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
timeInstantperiod, duration, pattern, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
timepattern, period, duration, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
timePeriodpattern, period, duration, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
datepattern, period, duration, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
monthpattern, period, duration, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
yearpattern, period, duration, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
centurypattern, period, duration, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
recurringDatepattern, period, duration, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
recurringDaypattern, period, duration, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
Constraint on Schemas: list of atomic
Validation Contribution: datatype valid
A sequence of character information items appearing in an instance document is schema-valid with respect to a datatype definition if:
  1. It is a member of the lexical space of the {base type definition};
  2. The member of the value space of the {base type definition} denoted by the sequence is facet valid (§4.2) with respect to each member of {facets}.

4.2 Constraining facets

This section provides the details of each constraining facet component.

constraining facets provide for:

Validation Contribution: facet valid
A member of a value space is schema-valid with respect to a constraining facet component if:
  1. the member is schema-valid with respect to the particular constraining facet as specified below.

4.2.1 length

length provides for:

Schema Componentlength
[value]
A nonNegativeInteger.
[annotation]
Optional. An annotation.
Constraint on Schemas: length and minLength
It is an error for both length and minLength to be members of {facets}.
Validation Contribution: length valid
A member of a value space is schema-valid with respect to length if:
  1. If {base type definition} is string, then the length of the value, as measured in [Unicode] code points, is equal to {value};
  2. If {base type definition} is binary, then the length of the value, as measured in octets of the binary data, is equal to {value};
  3. If {variety} is list, then the length of the value, as measured in list items, is equal to {value}

4.2.2 minLength

minLength provides for:

Schema ComponentminLength
[value]
A nonNegativeInteger.
[annotation]
Optional. An annotation.
Constraint on Schemas: minLength <= maxLength
If both minLength and maxLength are members of {facets}, then the {value} of minLength must be greater than the {value} of maxLength.
Validation Contribution: minLength valid
A member of a value space is schema-valid with respect to minLength if:
  1. If {base type definition} is string, then the length of the value, as measured in [Unicode] code points, is greater than or equal to {value};
  2. If {base type definition} is binary, then the length of the value, as measured in octets of binary data, is greater than or equal to {value};
  3. If {variety} is list, then the length of the value, as measured in list items, is greater than or equal to {value}

4.2.3 maxLength

maxLength provides for:

Schema ComponentmaxLength
[value]
A nonNegativeInteger.
[annotation]
Optional. An annotation.
Constraint on Schemas: length and maxLength
It is an error for both length and maxLength to be specified for the same datatype.
Validation Contribution: maxLength valid
A member of a value space is schema-valid with respect to maxLength if:
  1. If {base type definition} is string, then the length of the value, as measured in [Unicode] code points, is less than or equal to {value};
  2. If {base type definition} is binary, then the length of the value, as measured in octets of binary data, is less than or equal to {value};
  3. If {variety} is list, then the length of the value, as measured in list items, is less than or equal to {value}

4.2.4 pattern

pattern provides for:

Schema Componentpattern
[value]
A regular expression.
[annotation]
Optional. An annotation.
Validation Contribution: pattern valid
A member of a value space is schema-valid with respect to pattern if:
  1. the value is among the set of values denoted by literals which are among the set of strings denoted by the regular expression specified in {value}.

4.2.5 enumeration

enumeration provides for:

  • Constraining a value space to a specified set of values.
Schema Componentenumeration
[value]
A set of values from the value space of the {base type definition}.
[annotation]
Optional. An annotation.
Validation Contribution: enumeration valid
A member of a value space is schema-valid with respect to enumeration if:
  1. the value is one of the values specified in {value}.

4.2.6 maxInclusive

maxInclusive provides for:

Schema ComponentmaxInclusive
[value]
A value from the value space of the {base type definition}.
[annotation]
Optional. An annotation.
Constraint on Schemas: minInclusive <= maxInclusive
It is an error for the value specified for minInclusive to be greater than the value specified for maxInclusive for the same datatype.
Validation Contribution: maxInclusive valid
A member of a value space is schema-valid with respect to maxInclusive if:
  1. If {base type definition} is string (or anything derived from string), then the value is lexicographically less than or equal to {value};
  2. If the numeric property in {fundamental facets} is true, then the value is numerically less than or equal to {value};
  3. If the numeric property of {base type definition} is false (i.e., {base type definition} is one of the date and time related datatypes), then the value must be chronologically less than or equal to {value};

4.2.7 maxExclusive

maxExclusive provides for:

Schema ComponentmaxExclusive
[value]
A value from the value space of the {base type definition}.
[annotation]
Optional. An annotation.
Constraint on Schemas: maxInclusive and maxExclusive
It is an error for both maxInclusive and maxExclusive to be specified for the same datatype.
Constraint on Schemas: minExclusive <= maxExclusive
It is an error for the value specified for minExclusive to be greater than the value specified for maxExclusive for the same datatype.
Validation Contribution: maxExclusive valid
A member of a value space is schema-valid with respect to maxExclusive if:
  1. If {base type definition} is string (or anything derived from string), then the value must be lexicographically less than {value};
  2. If the numeric property of {base type definition} is true, then the value must be numerically less than {value};
  3. If the numeric property of {base type definition} is false (i.e., {base type definition} is one of the date and time related datatypes), then the value must be chronologically less than {value};

4.2.8 minExclusive

minExclusive provides for:

Schema ComponentminExclusive
[value]
A value from the value space of the {base type definition}.
[annotation]
Optional. An annotation.
Constraint on Schemas: minInclusive and minExclusive
It is an error for both minInclusive and minExclusive to be specified for the same datatype.
Validation Contribution: minExclusive valid
A member of a value space is schema-valid with respect to minExclusive if:
  1. If {base type definition} is string (or anything derived from string), then the value must be lexicographically greater than {value};
  2. If the numeric property of {base type definition} is true, then the value must be numerically greater than {value};
  3. If the numeric property of {base type definition} is false (i.e., {base type definition} is one of the date and time related datatypes), then the value must be chronologically greater than {value};

4.2.9 minInclusive

minInclusive provides for:

Schema ComponentminInclusive
[value]
A value from the value space of the {base type definition}.
[annotation]
Optional. An annotation.
Validation Contribution: minInclusive valid
A member of a value space is schema-valid with respect to minInclusive if:
  1. If {base type definition} is string (or anything derived from string), then the value must be lexicographically greater than or equal to {value};
  2. If the numeric property of {base type definition} is true, then the value must be numerically greater than or equal to {value};
  3. If the numeric property of {base type definition} is false (i.e., {base type definition} is one of the date and time related datatypes), then the value must be chronologically greater than or equal to {value};

4.2.10 precision

precision provides for:

  • Constraining a value space to values with a specific maximum number of decimal digits.
Schema Componentprecision
[value]
A positiveInteger.
[annotation]
Optional. An annotation.
Validation Contribution: precision valid
A member of a value space is schema-valid with respect to precision if:
  1. the number of decimal digits in the value is less than or equal to {value};

4.2.11 scale

scale provides for:

  • Constraining a value space to values with a specific maximum number of decimal digits in the fractional part.
Schema Componentscale
[value]
A nonNegativeInteger.
[annotation]
Optional. An annotation.
Constraint on Schemas: scale less than or equal to precision
It is an error for scale to be greater than precision.
Validation Contribution: scale valid
A member of a value space is schema-valid with respect to precision if:
  1. the number of decimal digits in the fractional part of the value is less than or equal to {value};

4.2.12 encoding

encoding provides for:

Schema Componentencoding
[value]
One of {hex, base64}.
[annotation]
Optional. An annotation.
NOTE: There are no Validity Contributions associated encoding.

4.2.13 duration

duration provides for:

  • Constraining a value space to values of a specific duration of time.
Schema Componentduration
[value]
A timeDuration.
[annotation]
Optional. An annotation.
NOTE: There are no Validity Contributions associated duration.

4.2.14 period

period provides for:

  • Constraining a value space to values of a specific frequency of recurrence.
Schema Componentperiod
[value]
A timeDuration.
[annotation]
Optional. An annotation.
NOTE: There are no Validity Contributions associated period.

5 XML representation of datatype definitions

The sections below define correspondences between element information items and datatype definition components. All the element information items in the XML representation of a datatype definition are in the XML Schema namespace, that is their [ namespace URI ] is http://www.w3.org/1999/XMLSchema.

Throughout the following sections, the [value] of an attribute information item or the [children] of an element information item means a string composed of, in order, the [character code] of each character information item in the [children] of that attribute information item or in the [children] of that element information item respectively.

5.1 XML representation of datatype definitions

The XML representation for a Datatype definition schema component is a simpleType element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation SummarysimpleType Element Information Item

<simpleType
  abstract = boolean
  base = QName
  derivedBy = | list | restriction  : restriction
  id = ID
  name = NCName>
  Content: ( annotation? , ( minExclusive | minInclusive | maxExclusive | maxInclusive | precision | scale | length | minLength | maxLength | encoding | period | duration | enumeration | pattern )* )
</simpleType>

Datatype Definition Schema Component
PropertyRepresentation
{name} The value of the name [attribute], if present, otherwise null
{base type definition} The value of the base [attribute]
{variety} list if the value of the derivedBy [attribute] (or the derivedBy [attribute] of {base type definition} or any of its any ancestor) is list; otherwise atomic.
{target namespace} The value of the targetNamespace [attribute] of the parent schema element information item.
{facets} The union of the set of facet components corresponding to the facet [children] of the item.
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null

A derived datatype can be derived from a primitive datatype or another derived datatype by one of two means: by restriction or by list.

5.1.1 Derivation by restriction

An atomic datatype can be derived from another atomic datatype by restricting its value space and, consequently, lexical space.

Example
An electronic commerce schema might define a datatype called Sku (the barcode number that appears on products) from the built-in datatype string by supplying a value for the pattern facet.
<simpleType name='Sku' base='string'>
    <pattern value='\d{3}-[A-Z]{2}'/>
</simpleType>
In this case, Sku is the name of the new user-derived datatype, string is its base type and pattern is the facet.

5.1.2 Derivation by list

A list dataype must be derived from an atomic datatype. This yields a list datatype that can contain whitespace separated lists of values of the base type.

Example
A system may want to store lists of floating point values.
<simpleType name='listOfFloat' base='float' derivedBy='list'/>
In this case, listOfFloat is the name of the new user-derived datatype, float is its base type and list is the derivation method.

As mentioned in List datatypes (§2.5.1.2), when a datatype is derived from a list datatype, the following constraining facets may be used:

For each of the above facets, the unit of length is measured in number of list items.

5.2 Constraining facets

This section details the XML Representation for specificing constraining facets in a datatype definition.

5.2.1 length

The XML representation for a length schema component is a length element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summarylength Element Information Item

<length
  id = ID
  value = nonNegativeInteger>
  Content: ( annotation? )
</length>

length Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following is the definition of a user-derived datatype to represent product codes which must be exactly 8 characters in length.
<simpleType name='productCode' base='string'>
    <length value='8'/>
</simpleType>

5.2.2 minLength

The XML representation for a minLength schema component is a minLength element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation SummaryminLength Element Information Item

<minLength
  id = ID
  value = nonNegativeInteger>
  Content: ( annotation? )
</minLength>

minLength Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following is the definition of a user-derived datatype which requires strings to have at least one character (i.e., the empty string is not in the value space of this datatype).
<simpleType name='non-empty-string' base='string'>
    <minLength value='1'/>
</simpleType>

5.2.3 maxLength

The XML representation for a maxLength schema component is a maxLength element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation SummarymaxLength Element Information Item

<maxLength
  id = ID
  value = nonNegativeInteger>
  Content: ( annotation? )
</maxLength>

maxLength Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following is the definition of a user-derived datatype which might be used to accept form input with an upper limit to the number of characters that are acceptable.
<simpleType name='form-input' base='string'>
    <maxLength value='50'/>
</simpleType>

5.2.4 pattern

The XML representation for a pattern schema component is a pattern element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summarypattern Element Information Item

<pattern
  id = ID
  value = string>
  Content: ( annotation? )
</pattern>

{value} must be a valid regular expression.
pattern Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Schema Representation Constraint: Multiple patterns
If multiple pattern element information items appear as [children] of a simpleType, the [value]s should be combined as if they appeared in a single regular expression as separate branches.
Example
The following is the definition of a user-derived datatype which is a better representation of postal codes in the United States, by limiting strings to those which are matched by a specific regular expression.
<simpleType name='better-us-zipcode' base='string'>
    <pattern value='[0-9]{5}(-[0-9]{4})?'/>
</simpleType>

5.2.5 enumeration

The XML representation for a enumeration schema component is a enumeration element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summaryenumeration Element Information Item

<enumeration
  id = ID
  value = string>
  Content: ( annotation? )
</enumeration>

{value} must be a valid value of the {base type definition}.
enumeration Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Schema Representation Constraint: Multiple patterns
If multiple enumeration element information items appear as [children] of a simpleType the {value} of the enumeration component should be the set of all such [value]s.
Example
The following example is a datatype definition for a user-derived datatype which limits the values of dates to the three US holidays enumerated. This datatype definition would appear in a schema authored by an "end-user" and shows how to define a datatype by enumerating the values in its value space. The enumerated values must be type-valid literals for the base type.
<simpleType name='holidays' base='recurringDate'>
    <annotation>
        <documentation>some US holidays</documentation>
    </annotation>
    <enumeration value='--01-01'>
        <annotation>
            <documentation>New Year's day</documentation>
        </annotation>
    </enumeration>
    <enumeration value='--07-04'/>
        <annotation>
            <documentation>4th of July</documentation>
        </annotation>
    </enumeration>
    <enumeration value='--12-25'/>
        <annotation>
            <documentation>Christmas</documentation>
        </annotation>
    </enumeration>
</simpleType>

5.2.6 maxInclusive

The XML representation for a maxInclusive schema component is a maxInclusive element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation SummarymaxInclusive Element Information Item

<maxInclusive
  id = ID
  value = string>
  Content: ( annotation? )
</maxInclusive>

{value} must be a valid value of the {base type definition}.
maxInclusive Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following is the definition of a user-derived datatype which limits values to integers less than or equal to 100, using maxInclusive.
<simpleType name='one-hundred-or-less' base='integer'>
    <maxInclusive value='100'/>
</simpleType>

5.2.7 maxExclusive

The XML representation for a maxExclusive schema component is a maxExclusive element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation SummarymaxExclusive Element Information Item

<maxExclusive
  id = ID
  value = string>
  Content: ( annotation? )
</maxExclusive>

{value} must be a valid value of the {base type definition}.
maxExclusive Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following is the definition of a user-derived datatype which limits values to integers less than or equal to 100, using maxExclusive.
<simpleType name='less-than-one-hundred-and-one' base='integer'>
    <maxExclusive value='101'/>
</simpleType>
Note that the value space of this datatype is identical to the previous one (named 'one-hundred-or-less').

5.2.8 minInclusive

The XML representation for a minInclusive schema component is a minInclusive element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation SummaryminInclusive Element Information Item

<minInclusive
  id = ID
  value = string>
  Content: ( annotation? )
</minInclusive>

{value} must be a valid value of the {base type definition}.
minInclusive Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following is the definition of a user-derived datatype which limits values to integers greater than or equal to 100, using minInclusive.
<simpleType name='one-hundred-or-more' base='integer'>
    <minInclusive value='100'/>
</simpleType>

5.2.9 minExclusive

The XML representation for a minExclusive schema component is a minExclusive element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation SummaryminExclusive Element Information Item

<minExclusive
  id = ID
  value = string>
  Content: ( annotation? )
</minExclusive>

{value} must be a valid value of the {base type definition}.
minExclusive Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following is the definition of a user-derived datatype which limits values to integers greater than or equal to 100, using minExclusive.
<simpleType name='more-than-ninety-nine' base='integer'>
    <minExclusive value='99'/>
</simpleType>
Note that the value space of this datatype is identical to the previous one (named 'one-hundred-or-more').

5.2.10 precision

The XML representation for a precision schema component is a precision element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summaryprecision Element Information Item

<precision
  id = ID
  value = nonNegativeInteger>
  Content: ( annotation? )
</precision>

precision Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following is the definition of a user-derived datatype which could be used to represent monetary amounts, such as in a financial management application which does not have figures above $1M and only allow whole cents. This definition would appear in a schema authored by an "end-user" and shows how to define a datatype by specifying facet values which constrain the range of the base type in a manner specific to the base type (different than specifying max/min values as before).
<simpleType name='amount' base='decimal'>
    <precision value='8'/>
    <scale value='2'/>
</simpleType>

5.2.11 scale

The XML representation for a scale schema component is a scale element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summaryscale Element Information Item

<scale
  id = ID
  value = nonNegativeInteger>
  Content: ( annotation? )
</scale>

scale Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following is the definition of a user-derived datatype which could be used to represent the magnitude of a person's body temperature on the farenheit scale. This definition would appear in a schema authored by an "end-user" and shows how to define a datatype by specifying facet values which constrain the range of the base type.
<simpleType name='farenheitBodyTemp' base='decimal'>
    <precision value='4'/>
    <scale value='1'/>
    <minInclusive value='97.5'/>
    <maxInclusive value='105.0'/>
  </simpleType>

5.2.12 encoding

The XML representation for a encoding schema component is a encoding element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summaryencoding Element Information Item

<encoding
  id = ID
  value = | hex | base64 >
  Content: ( annotation? )
</encoding>

encoding Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
The following example is a datatype definition for a user-derived datatype whose value space is the set of binary streams of length 4 octets (32 bits) and whose lexical space is the set of base64 encodings of such binary streams. This datatype definition would appear in a schema authored by an "end-user" and shows how to define a datatype by specifying multiple constraining facets.
<simpleType name='myBinary' base='binary'>
    <length value='4'/>
    <encoding value='base64'/>
</simpleType>

5.2.13 duration

The XML representation for a duration schema component is a duration element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summaryduration Element Information Item

<duration
  id = ID
  value = timeDuration>
  Content: ( annotation? )
</duration>

duration Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
Suppose an HMO wanted to define the length of a hospital stay permitted for the birth of a baby as two days. They may want to define a datatype as below.
<simpleType name='birthingStay' base='timePeriod'>
    <duration value='P2D'/>
</simpleType>

5.2.14 period

The XML representation for a period schema component is a period element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summaryperiod Element Information Item

<period
  id = ID
  value = timeDuration>
  Content: ( annotation? )
</period>

period Schema Component
PropertyRepresentation
{value} The value of the value [attribute]
{annotation} The annotation corresponding to the annotation element information item in the [children], if present, otherwise null
Example
Suppose we wanted to define a day of the week i.e. a 24 hour duration that recurs every 7 days. This could be done as follows:
<simpleType name='dayOfWeek' base='recurringDuration'>
    <duration value='PT24H'/>
    <period value='P7D'/>
</simpleType>

6 Conformance

This specification describes two levels of conformance for datatype processors. The first is required of all processors. Support for the other will depend on the application environments for which the processor is intended.

[Definition:]   Minimally conforming processors must completely and correctly implement the Constraint on Schemas and Validity Contribution.

[Definition:]   Processors which accept schemas in the form of XML documents as described in XML representation of datatype definitions (§5.1) are additionally said to provide conformance to the XML Representation of Schemas, and must, when processing schema documents, completely and correctly implement all Schema Representation Constraints in this specification, and must adhere exactly to the specifications in XML representation of datatype definitions (§5.1) for mapping the contents of such documents to schema components for use in validation.

NOTE: By separating the conformance requirements relating to the concrete syntax of XML schema documents, this specification admits processors which validate using schemas stored in optimised binary representations, dynamically created schemas represented as programming language data structures, or implementations in which particular schemas are compiled into executable code such as C or Java. Such processors can be said to be minimally conforming but not necessarily in conformance to the XML Representation of Schemas.

A Schema for Datatype Definitions (normative)


<?xml version='1.0'?>
<!-- XML Schema schema for XML Schemas: Part 2: Datatypes -->
<!-- Note this schema is NOT the normative datatypes schema - - the
     prose copy in the datatypes REC is the normative version (which
     shouldn't differ from this one except for this comment and entity
     expansions, but just in case -->
<!DOCTYPE schema PUBLIC "-//W3C//DTD XMLSCHEMA 19991216//EN"
    "structures.dtd" [
  <!ATTLIST element xmlns:x CDATA #IMPLIED><!-- keep this schema XML1.0 valid -->
  <!ELEMENT has-facet EMPTY>
  <!ATTLIST has-facet name NMTOKEN #REQUIRED>
  <!ELEMENT has-property EMPTY>
  <!ATTLIST has-property name NMTOKEN #REQUIRED
    value CDATA #REQUIRED>
  ]>
<schema xmlns="&XMLSchemaNS;" targetNamespace="&XMLSchemaNS;"
  version="$Id: datatypes.html,v 1.1 2015-01-05 08:51:44 denis Exp $">

  <import namespace="http://www.w3.org/XML/1998/namespace"
    schemaLocation="../structures/xml.xsd">
   <annotation>
    <documentation>Get access to the xml: attribute groups for xml:lang
    </documentation>
   </annotation>
  </import>

  <annotation>
   <documentation>First the builtin primitive datatypes.
                  These definitions are for information only, the
                  real builtin definitions are magic.</documentation>
  </annotation>
 
 <simpleType name="urSimpleType" base="urSimpleType"/>

<simpleType name="string" base="urSimpleType">
  <annotation>
     <appinfo>
      <has-facet name="length"/>
       <has-facet name="minLength"/>
       <has-facet name="maxLength"/>
       <has-facet name="pattern"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
 </simpleType>

 <simpleType name="boolean" base="urSimpleType">
    <annotation>
     <appinfo>
      <has-facet name="pattern"/>
      <has-property name="ordered" value="false"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
 </simpleType>
 
 <simpleType name="float" base="urSimpleType">
   <annotation>
     <appinfo>
      <has-facet name="pattern"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
   </annotation>
 </simpleType>

 <simpleType name="double" base="urSimpleType">
    <annotation>
     <appinfo>
      <has-facet name="pattern"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
 </simpleType>

 <simpleType name="decimal" base="urSimpleType">
    <annotation>
     <appinfo>
      <has-facet name="precision"/>
       <has-facet name="scale"/>
       <has-facet name="pattern"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
   </annotation>
 </simpleType>

 <simpleType name="timeDuration" base="urSimpleType">
    <annotation>
     <appinfo>
      <has-facet name="pattern"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
 </simpleType>

 <simpleType name="recurringDuration" base="urSimpleType">
    <annotation>
     <appinfo>
      <has-facet name="duration"/>
       <has-facet name="period"/>
            <has-facet name="pattern"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
       <has-property name="ordered" value="false"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
 </simpleType>

 <simpleType name="binary" base="urSimpleType">
    <annotation>
     <appinfo>
      <has-facet name="encoding"/>
       <has-facet name="length"/>
       <has-facet name="minLength"/>
       <has-facet name="maxLength"/>
       <has-facet name="pattern"/>
       <has-facet name="enumeration"/>
      <has-property name="ordered" value="false"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
 </simpleType>

 <simpleType name="uriReference" base="urSimpleType">
    <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-property name="ordered" value="false"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
 </simpleType>

 <simpleType name="ID" base="urSimpleType">
   <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
 </simpleType>

 <simpleType name="IDREF" base="urSimpleType">
   <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
 </simpleType>

 <simpleType name="ENTITY" base="urSimpleType">
   <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
 </simpleType>

 <simpleType name="NOTATION" base="urSimpleType">
   <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
 </simpleType>

 <simpleType name="QName" base="urSimpleType">
     <annotation>
      <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
      </annotation>
  </simpleType>

  <annotation>
   <documentation>Now the derived primitive types</documentation>
  </annotation>

  <simpleType name="language" base="string">
     <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
      </annotation>
    <pattern value="([a-zA-Z]{2}|[iI]-[a-zA-Z]+|[xX]-[a-zA-Z]+)(-[a-zA-Z]+)*">
      <annotation>
        <documentation source="http://www.w3.org/TR/REC-xml#NT-LanguageID">
          pattern matches production 33 from the XML spec
        </documentation>
      </annotation>
    </pattern>
  </simpleType>
  
  <simpleType name="IDREFS" base="IDREF" derivedBy="list">
   <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="enumeration"/>
      <has-property name="ordered" value="false"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
  </simpleType>

  <simpleType name="ENTITIES" base="ENTITY" derivedBy="list">
   <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="enumeration"/>
      <has-property name="ordered" value="false"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
  </simpleType>

  <simpleType name="NMTOKEN" base="string">
     <annotation>
      <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
      </annotation>
    <pattern value="\c+">
      <annotation>
        <documentation source="http://www.w3.org/TR/REC-xml#NT-Nmtoken">
          pattern matches production 7 from the XML spec
        </documentation>
      </annotation>
    </pattern>
  </simpleType>
  
  <simpleType name="NMTOKENS" base="NMTOKEN" derivedBy="list">
   <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="enumeration"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
  </simpleType>

  <simpleType name="Name" base="string">
     <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
      </annotation>
    <pattern value="\i\c*">
      <annotation>
        <documentation source="http://www.w3.org/TR/REC-xml#NT-Name">
          pattern matches production 5 from the XML spec
        </documentation>
      </annotation>
    </pattern>
  </simpleType>

  <simpleType name="NCName" base="Name">
     <annotation>
    <appinfo>
      <has-facet name="length"/>
      <has-facet name="minLength"/>
      <has-facet name="maxLength"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
  <pattern value="[\i-[:]][\c-[:]]*">
      <annotation>
        <documentation source="http://www.w3.org/TR/REC-xml-names/#NT-NCName">
          pattern matches production 4 from the Namespaces in XML spec
        </documentation>
     </annotation>
    </pattern>
  </simpleType>
  
  <simpleType name="integer" base="decimal">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <scale value="0"/>
  </simpleType>
        
  <simpleType name="nonPositiveInteger" base="integer">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <maxInclusive value="0"/>
  </simpleType>

  <simpleType name="negativeInteger" base="nonPositiveInteger">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <maxInclusive value="-1"/>
  </simpleType>

  <simpleType name="long" base="integer">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <minInclusive value="-9223372036854775808"/>
    <maxInclusive value="9223372036854775807"/>
  </simpleType>

  <simpleType name="int" base="long">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <minInclusive value="-2147483648"/>
    <maxInclusive value="2147483647"/>
  </simpleType>
  
  <simpleType name="short" base="int">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <minInclusive value="-32768"/>
    <maxInclusive value="32767"/>
  </simpleType>
  
  <simpleType name="byte" base="short">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <minInclusive value="-128"/>
    <maxInclusive value="127"/>
  </simpleType>
  
  <simpleType name="nonNegativeInteger" base="integer">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <minInclusive value="0"/>
  </simpleType>

  <simpleType name="unsignedLong" base="nonNegativeInteger">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <maxInclusive value="18446744073709551615"/>
  </simpleType>
  
  <simpleType name="unsignedInt" base="unsignedLong">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <maxInclusive value="4294967295"/>
  </simpleType>
  
  <simpleType name="unsignedShort" base="unsignedInt">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <maxInclusive value="65535"/>
  </simpleType>
  
  <simpleType name="unsignedByte" base="unsignedShort">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <maxInclusive value="255"/>
  </simpleType>
  
  <simpleType name="positiveInteger" base="nonNegativeInteger">
   <annotation>
    <appinfo>
      <has-facet name="precision"/>
      <has-facet name="scale"/>
      <has-facet name="pattern"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="true"/>
      <has-property name="cardinality" value="finite"/>
      <has-property name="numeric" value="true"/>
    </appinfo>
  </annotation>
    <minInclusive value="1"/>
  </simpleType>

  <simpleType name="timeInstant" base="recurringDuration">
    <annotation>
     <appinfo>
      <has-facet name="period"/>
      <has-facet name="duration"/>    
      <has-facet name="pattern"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
  <duration value="P0Y"/>
  <period value="P0Y"/>
  </simpleType>

  <simpleType name="time" base="recurringDuration">
   <annotation>
    <appinfo>
      <has-facet name="pattern"/>
      <has-facet name="period"/>
      <has-facet name="duration"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
    <period value="PT24H"/>
  <duration value="P0Y"/>
  </simpleType>

  <simpleType name="timePeriod" base="recurringDuration">
    <annotation>
     <appinfo>
      <has-facet name="pattern"/>
      <has-facet name="period"/>
      <has-facet name="duration"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
  <period value="P0Y"/>
  </simpleType>

  <simpleType name="date" base="timePeriod">
   <annotation>
    <appinfo>
      <has-facet name="pattern"/>
      <has-facet name="period"/>
      <has-facet name="duration"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
    <duration value="PT24"/>
  </simpleType>

  <simpleType name="month" base="timePeriod">
   <annotation>
    <appinfo>
      <has-facet name="pattern"/>
      <has-facet name="period"/>
      <has-facet name="duration"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
    <duration value="P1M"/>
  </simpleType>

  <simpleType name="year" base="timePeriod">
   <annotation>
    <appinfo>
      <has-facet name="pattern"/>
      <has-facet name="period"/>
      <has-facet name="duration"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
    <period value="P1Y"/>
  </simpleType>

  <simpleType name="century" base="timePeriod">
   <annotation>
    <appinfo>
      <has-facet name="pattern"/>
      <has-facet name="period"/>
      <has-facet name="duration"/>
      <has-facet name="enumeration"/>
      <has-facet name="maxInclusive"/>
      <has-facet name="maxExclusive"/>
      <has-facet name="minInclusive"/>
      <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
  </annotation>
    <period value="P100Y"/>
  </simpleType>

  <simpleType name="recurringDate" base="recurringDuration">
    <annotation>
     <appinfo>
      <has-facet name="pattern"/>
      <has-facet name="period"/>
      <has-facet name="duration"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
  <duration value="P24H"/>
  <period value="P1Y"/>
  </simpleType>

  <simpleType name="recurringDay" base="recurringDuration">
    <annotation>
     <appinfo>
      <has-facet name="pattern"/>
      <has-facet name="period"/>
      <has-facet name="duration"/>
       <has-facet name="enumeration"/>
       <has-facet name="maxInclusive"/>
       <has-facet name="maxExclusive"/>
       <has-facet name="minInclusive"/>
       <has-facet name="minExclusive"/>
      <has-property name="ordered" value="true"/>
      <has-property name="bounded" value="false"/>
      <has-property name="cardinality" value="countably infinite"/>
      <has-property name="numeric" value="false"/>
    </appinfo>
   </annotation>
  <duration value="P24H"/>
  <period value="P1M"/>
  </simpleType>

  <complexType name="openAttrs" content="empty">
   <annotation>
    <documentation>This type is extended by almost all schema types
                   to allow attributes from other namespaces to be
                   added to user schemas.</documentation>
   </annotation>
   <anyAttribute namespace="##other"/>
  </complexType>

  <complexType name="annotated" base="openAttrs" derivedBy="extension" content="elementOnly">
   <annotation>
    <documentation>This type is extended by all types which allow annotation
          other than &lt;schema> itself</documentation>
   </annotation>
   <element ref="annotation" minOccurs="0"/>
   <attribute name="id" type="ID"/>
  </complexType>

   <annotation>
    <documentation>All the things which can occur in any of the
                   attributes controlling derivation or use of derived 
                   definitions</documentation>
    <documentation>A utility type, not for public use</documentation>
   </annotation>
   <enumeration value="list"/>
   <enumeration value="restriction"/>
  </simpleType>

  <complexType name="simpleType" base="annotated" derivedBy="extension" abstract="true">
    <element ref="facet" minOccurs="0" maxOccurs="unbounded"/>
    <attribute name="name" type="NCName">
      <annotation>
       <documentation>Can be restricted to required or forbidden</documentation>
      </annotation>
    </attribute>
    <attribute name="base" type="QName" use="required"/>
     <simpleType base="NMTOKEN">
      <enumeration value="list"/>
      <enumeration value="restriction"/>
     </simpleType>
    </attribute>
  </complexType>

  <complexType name="topLevelSimpleType" base="simpleType" derivedBy="restriction">
   <element ref="annotation" minOccurs="0"/>
   <element ref="facet" minOccurs="0" maxOccurs="unbounded"/>
   <attribute name="name" use="required" type="NCName">
    <annotation><documentation>Required at the top level</documentation></annotation>
   </attribute>   
  </complexType>

  <complexType name="localSimpleType" base="simpleType" derivedBy="restriction">
   <element ref="annotation" minOccurs="0"/>
   <element ref="facet" minOccurs="0" maxOccurs="unbounded"/>
   <attribute name="name" use="prohibited">
    <annotation><documentation>Forbidden when nested</documentation></annotation>
   </attribute>   
  </complexType>

  <element name="simpleType" equivClass="schemaTop" type="topLevelSimpleType"/>

  <complexType name="facet" base="annotated" derivedBy="extension">
    <attribute name="value" use="required"/>
  </complexType>

  <element name="facet" type="facet" abstract="true"/>

  <element name="minBound" abstract="true" equivClass="facet"/>

  <element name="minExclusive" equivClass="minBound"/>
  <element name="minInclusive" equivClass="minBound"/>

  <element name="maxBound" abstract="true" equivClass="facet"/>

  <element name="maxExclusive" equivClass="maxBound"/>
  <element name="maxInclusive" equivClass="maxBound"/>

  <complexType name="numFacet" base="facet" derivedBy="restriction">
    <attribute name="value" type="nonNegativeInteger"/>
  </complexType>

  <element name="precision" type="numFacet" equivClass="facet"/>
  <element name="scale" type="numFacet" equivClass="facet"/>

  <element name="length" type="numFacet" equivClass="facet"/>
  <element name="minLength" type="numFacet" equivClass="facet"/>
  <element name="maxLength" type="numFacet" equivClass="facet"/>

  <element name="encoding" equivClass="facet">
   <complexType base="facet" derivedBy="restriction">
     <attribute name="value">
      <simpleType base="NMTOKEN">
       <annotation>
  <documentation>A utility type, not for public use</documentation>
       </annotation>
  <enumeration value="hex">
    <annotation>
      <documentation>each (8-bit) byte is encoded as a sequence
      of 2 hexidecimal digits</documentation>
    </annotation>
  </enumeration>
  <enumeration value="base64">
    <annotation>
      <documentation>value is encoded in Base64 as defined
                           in the MIME RFC</documentation>
    </annotation>
  </enumeration>
      </simpleType>
     </attribute>
   </complexType>
  </element>

  <element name="period" equivClass="facet">
   <complexType base="facet" derivedBy="restriction">
     <attribute name="value" type="timeDuration"/>
   </complexType>
  </element>

  <element name="duration" equivClass="facet">
   <complexType base="facet" derivedBy="restriction">
     <attribute name="value" type="timeDuration"/>
   </complexType>
  </element>
  
  <element name="enumeration" equivClass="facet"/>

  <element name="pattern" equivClass="facet"/>

  <element name="appinfo">
    <complexType content="mixed">
      <any minOccurs="0" maxOccurs="unbounded" processContents="lax"/>
      <attribute name="source" type="uriReference"/>
    </complexType>
  </element>

  <element name="documentation" xmlns:x="http://www.w3.org/XML/1998/namespace">
    <complexType content="mixed">
      <any minOccurs="0" maxOccurs="unbounded" processContents="lax"/>
      <attribute name="source" type="uriReference"/>
      <attributeGroup ref="x:specialAttrs"/>
    </complexType>
  </element>

  <element name="annotation">
   <complexType>
    <choice minOccurs="0" maxOccurs="unbounded">
     <element ref="appinfo"/>
     <element ref="documentation"/>
    </choice>
   </complexType>
  </element>

</schema>

B DTD for Datatype Definitions (normative)


<!-- DTD for XML Schemas: Part 2: Datatypes -->
<!-- $Id: datatypes.html,v 1.1 2015-01-05 08:51:44 denis Exp $ -->
<!-- Note this DTD is NOT the normative datatypes DTD - - the
     prose copy in the datatypes REC is the normative version (which
     shouldn't differ from this one except for this comment and entity
     expansions, but just in case -->
<!ENTITY % p ''> <!-- can be overriden in the internal subset of a
                      schema document to establish a namespace prefix -->
<!-- Define all the element names, with optional prefix -->
<!ENTITY % simpleType "%p;simpleType">
<!ENTITY % maxExclusive "%p;maxExclusive">
<!ENTITY % minExclusive "%p;minExclusive">
<!ENTITY % maxInclusive "%p;maxInclusive">
<!ENTITY % minInclusive "%p;minInclusive">
<!ENTITY % precision "%p;precision">
<!ENTITY % scale "%p;scale">
<!ENTITY % length "%p;length">
<!ENTITY % minLength "%p;minLength">
<!ENTITY % maxLength "%p;maxLength">
<!ENTITY % enumeration "%p;enumeration">
<!ENTITY % pattern "%p;pattern">
<!ENTITY % encoding "%p;encoding">
<!ENTITY % period "%p;period">
<!ENTITY % duration "%p;duration">

<!-- Customisation entities for the ATTLIST of each element type.
     Define one of these if your schema takes advantage of the
     anyAttribute='##other' in the schema for schemas -->

<!ENTITY % simpleTypeAttrs ''>
<!ENTITY % maxExclusiveAttrs ''>
<!ENTITY % minExclusiveAttrs ''>
<!ENTITY % maxInclusiveAttrs ''>
<!ENTITY % minInclusiveAttrs ''>
<!ENTITY % precisionAttrs ''>
<!ENTITY % scaleAttrs ''>
<!ENTITY % lengthAttrs ''>
<!ENTITY % minLengthAttrs ''>
<!ENTITY % maxLengthAttrs ''>
<!ENTITY % enumerationAttrs ''>
<!ENTITY % patternAttrs ''>
<!ENTITY % encodingAttrs ''>
<!ENTITY % periodAttrs ''>
<!ENTITY % durationAttrs ''>
<!ENTITY % appinfoAttrs ''>
<!ENTITY % documentationAttrs ''>


<!-- annotation elements -->
<!ENTITY % annotation "%p;annotation">
<!ENTITY % appinfo "%p;appinfo">
<!ENTITY % documentation "%p;documentation">


<!-- Define some entities for informative use as attribute types -->
<!ENTITY % URIref "CDATA">
<!ENTITY % QName "CDATA">
<!ENTITY % NCName "NMTOKEN">
<!ENTITY % nonNegativeInteger "NMTOKEN">
<!ENTITY % boolean "(true|false)">

<!-- Note that the use of 'facet' below is less restrictive than is
     really intended:  There should in fact be no more than one of each of
     minInclusive, minExclusive, maxInclusive, maxExclusive,
     precision, scale,
     length, maxLength, minLength, encoding, period within datatype,
     and the min- and max- variants of Inclusive and Exclusive are
     mutually exclusive.
     On the other hand,  pattern and enumeration may repeat -->
<!ENTITY % minBound '(%minInclusive; | %minExclusive;)'>
<!ENTITY % maxBound '(%maxInclusive; | %maxExclusive;)'>
<!ENTITY % bounds '%minBound; | %maxBound;'>
<!ENTITY % numeric '%precision; | %scale;'>
<!ENTITY % ordered '%bounds; | %numeric;'>
<!ENTITY % unordered
   '%pattern; | %enumeration; | %length; | %maxLength; | %minLength;
    | %encoding; | %period; | %duration;'>
<!ENTITY % facet '%ordered; | %unordered;'>
<!ENTITY % facetAttr 'value CDATA #REQUIRED'>
<!ENTITY % facetModel '(%annotation;)?'>
<!ELEMENT %simpleType; ((%annotation;)?,(%facet;)*)>
<!ATTLIST %simpleType;
    name      %NCName;                 #IMPLIED
    base      %QName;                  #REQUIRED
    %simpleTypeAttrs;>
<!-- name is required at top level -->

<!ELEMENT %maxExclusive; %facetModel;>
<!ATTLIST %maxExclusive; %facetAttr;
          %maxExclusiveAttrs;>
<!ELEMENT %minExclusive; %facetModel;>
<!ATTLIST %minExclusive; %facetAttr;
          %minExclusiveAttrs;>

<!ELEMENT %maxInclusive; %facetModel;>
<!ATTLIST %maxInclusive; %facetAttr;
          %maxInclusiveAttrs;>
<!ELEMENT %minInclusive; %facetModel;>
<!ATTLIST %minInclusive; %facetAttr;
          %minInclusiveAttrs;>

<!ELEMENT %precision; %facetModel;>
<!ATTLIST %precision; %facetAttr;
          %precisionAttrs;>
<!ELEMENT %scale; %facetModel;>
<!ATTLIST %scale; %facetAttr;
          %scaleAttrs;>

<!ELEMENT %length; %facetModel;>
<!ATTLIST %length; %facetAttr;
          %lengthAttrs;>
<!ELEMENT %minLength; %facetModel;>
<!ATTLIST %minLength; %facetAttr;
          %minLengthAttrs;>
<!ELEMENT %maxLength; %facetModel;>
<!ATTLIST %maxLength; %facetAttr;
          %maxLengthAttrs;>

<!-- This one can be repeated -->
<!ELEMENT %enumeration; %facetModel;>
<!ATTLIST %enumeration; %facetAttr;
          %enumerationAttrs;>

<!-- This one can be repeated -->
<!ELEMENT %pattern; %facetModel;>
<!ATTLIST %pattern; %facetAttr;
          %patternAttrs;>

<!ELEMENT %encoding; %facetModel;>
<!ATTLIST %encoding; %facetAttr;
          %encodingAttrs;>
<!ELEMENT %period; %facetModel;>
<!ATTLIST %period; %facetAttr;
          %periodAttrs;>
<!ELEMENT %duration; %facetModel;>
<!ATTLIST %duration; %facetAttr;
          %durationAttrs;>

<!-- Annotation is either application information or documentation -->
<!-- By having these here they are available for datatypes as well
     as all the structures elements -->

<!ELEMENT %annotation; (%appinfo; | %documentation;)*>

<!-- User must define annotation elements in internal subset for this
     to work -->
<!ELEMENT %appinfo; ANY>   <!-- too restrictive -->
<!ATTLIST %appinfo;
          source     %URIref;      #IMPLIED
          %appinfoAttrs;>
<!ELEMENT %documentation; ANY>   <!-- too restrictive -->
<!ATTLIST %documentation;
          source     %URIref;   #IMPLIED
          xml:lang   CDATA      #IMPLIED
          %documentationAttrs;>

C Datatypes and Facets

C.1 Fundamental Facets

The following table shows the values of the fundamental facets for each built-in datatype.

 Datatypeorderedboundedcardinalitynumeric
primitivestringtruefalsecountably infinitefalse
booleanfalsefalsefinitefalse
floattruetruefinitetrue
doubletruetruefinitetrue
decimaltruefalsecountably infinitetrue
timeDurationtruefalsecountably infinitefalse
recurringDurationfalsefalsecountably infinitefalse
binaryfalsefalsecountably infinitefalse
uriReferencefalsefalsecountably infinitefalse
IDtruefalsecountably infinitefalse
IDREFtruefalsecountably infinitefalse
ENTITYtruefalsecountably infinitefalse
NOTATIONtruefalsecountably infinitefalse
QNametruefalsecountably infinitefalse
derivedlanguagetruefalsecountably infinitefalse
IDREFSfalsefalsecountably infinitefalse
ENTITIESfalsefalsecountably infinitefalse
NMTOKENtruefalsecountably infinitefalse
NMTOKENStruefalsecountably infinitefalse
Nametruefalsecountably infinitefalse
NCNametruefalsecountably infinitefalse
integertruefalsecountably infinitetrue
nonPositiveIntegertruefalsecountably infinitetrue
negativeIntegertruefalsecountably infinitetrue
longtruetruefinitetrue
inttruetruefinitetrue
shorttruetruefinitetrue
bytetruetruefinitetrue
nonNegativeIntegertruetruefinitetrue
unsignedLongtruetruefinitetrue
unsignedInttruetruefinitetrue
unsignedShorttruetruefinitetrue
unsignedBytetruetruefinitetrue
positiveIntegertruetruefinitetrue
timeInstanttruefalsecountably infinitefalse
timetruefalsecountably infinitefalse
timePeriodtruefalsecountably infinitefalse
datetruefalsecountably infinitefalse
monthtruefalsecountably infinitefalse
yeartruefalsecountably infinitefalse
centurytruefalsecountably infinitefalse
recurringDatetruefalsecountably infinitefalse
recurringDaytruefalsecountably infinitefalse

C.2 Constraining Facets

The constraining facets are listed below with all the primitive and derived datatypes that they apply to.

length applies to the following datatypes:

minLength applies to the following datatypes:

maxLength applies to the following datatypes:

pattern applies to the following datatypes:

enumeration applies to the following datatypes:

maxInclusive applies to the following datatypes:

maxExclusive applies to the following datatypes:

minInclusive applies to the following datatypes:

minExclusive applies to the following datatypes:

precision applies to the following datatypes:

scale applies to the following datatypes:

encoding applies to the following datatypes:

duration applies to the following datatypes:

period applies to the following datatypes:

D ISO 8601 Date and Time Formats

D.1 ISO 8601 Conventions

The two primitive datatypes described above, timeDuration, recurringDuration, and the five derived dataypes timeInstant, date, time, timePeriod, and recurringDate use lexical formats inspired by [ISO 8601]. This appendix provides more detail on the ISO formats and discusses some deviations from them for the datatypes defined in this specification.

[ISO 8601] "specifies the representation of dates in the Gregorian calendar and times and representations of periods of time". It should be pointed out that the datatypes described in this specification do not cover all the types of data covered by [ISO 8601], nor do they support all the lexical representations for those types of data. Specifically, we permit only a single lexical representation for each datatype.

[ISO 8601] lexical formats are described using "pictures" in which characters are used in place of digits. These characters have the following meanings:

  • C -- represents a digit used in the thousands and hundreds components, the "century" component, of the time element "year". Legal values are from 0 to 9.
  • Y -- represents a digit used in the tens and units components of the time element "year". Legal values are from 0 to 9.
  • M -- represents a digit used in the time element "month". The two digits in a MM format can have values from 1 to 12.
  • D -- represents a digit used in the time element "day". The two digits in a DD format can have values from 1 to 28 if the month value equals 2, 1 to 29 if the month value equals 2 and the year is a leap year, 1 to 30 if the month value equals 4, 6, 9 or 11, and 1 to 31 if the month value equals 1, 3, 5, 7, 8, 10 or 12.
  • h -- represents a digit used in the time element "hour". The two digits in a hh format can have values from 0 to 12.
  • m -- represents a digit used in the time element "minute". The two digits in a mm format can have values from 0 to 60.
  • s -- represents a digit used in the time element "second". The two digits in a ss format can have values from 0 to 60. In the formats described in this specification the whole number of seconds may be followed by decimal seconds to an arbitrary level of precision. This is represented in the picture by "ss.sss".

For all the information items indicated by the above characters, leading zeros are required where indicated.

In addition to the above, certain characters are used as designators and appear as themselves in lexical formats.

  • T -- is used as time designator to indicate the start of the representation of the time of day in recurringDuration and timeInstant
  • Z -- is used as time-zone designator, immediately (without a space) following a data element expressing the time of day in Coordinated Universal Time (UTC) in recurringDuration, timeInstant and time

D.2 Truncated and Reduced Formats -- Changed Heading for Section

[ISO 8601] supports a variety of "truncated" formats in which some of the characters on the left of specific formats, for example, the century, can be omitted. Truncated formats are, in general, not permitted for the datatypes defined in this specification with three exceptions. The time datatype uses a truncated format for timeInstant. By truncating the date information we represent an instant of time that recurs every day. Similarly, the recurringDate and recurringDay datatypes use left-truncated formats for date.

[ISO 8601] also supports a variety of "reduced" or right-truncated formats in which some of the characters to the right of specific formats, such as the time specification, can be omitted. Right truncated formats are also, in general, not permitted for the datatypes defined in this specification with the following exceptions: right-truncated representations of timePeriod are used as lexical representations for date, month, year and century.

D.3 Deviations from ISO 8601 Formats

D.3.1 Sign Allowed

An optional minus sign is allowed immediately preceding, without a space, the lexical representations for timeInstant and date. The year "0000" is an illegal year value.

D.3.2 More Than 9999 Years

To accommodate year values greater than 9999, more than four digits are allowed in the year representations of timeInstant, timeInstant and time. This follows the [ISO 8601 Draft Revision].

E Regular Expressions

A regular expression R is a sequence of characters that denote a set of strings L(R). When used to constrain a lexical space, a regular expression R asserts that only strings in L(R) are valid literals for values of that type.

[Definition:]  A regular expression is composed from zero or more branches, separated by | characters.

For all branches S, and for all regular expressions T, valid regular expressions R are: Denoting the set of strings L(R) containing:
(empty string) the set containing just the empty string
S all strings in L(S)
S|T all strings in L(S) and all strings in L(T)

[Definition:]  A branch consists of zero or more pieces, concatenated together.

For all pieces S, and for all branches T, valid branches R are: Denoting the set of strings L(R) containing:
S all strings in L(S)
ST all strings st with s in L(S) and t in L(T)

[Definition:]  A piece is an atom, possibly followed by a quantifier.

For all atoms S and non-negative integers n, m such that n <= m, valid pieces R are: Denoting the set of strings L(R) containing:
S all strings in L(S)
S? the empty string, and all strings in L(S).
S* All strings in L(S?) and all strings st with s in L(S*) and t in L(S). ( all concatenations of zero or more strings from L(S) )
S+ All strings st with s in L(S) and t in L(S*). ( all concatenations of one or more strings from L(S) )
S{n,m} All strings st with s in L(S) and t in L(S{n-1,m-1}). ( All sequences of at least n, and at most m, strings from L(S) )
S{0,m} All strings st with s in L(S?) and t in L(S{0,m-1}). ( All sequences of at most m, strings from L(S) )
S{n,} All strings in L(S{n,n}S*)
S{0,0} The set containing only the empty string
NOTE: The regular expression language in the Perl Programming Language [Perl] does not include a quantifier of the form S{,m), since it it logicall equivalent to S{0,m}. We have, therefore, left this logical possibility out of the regular expression language defined by this specification. We welcome further input from implementors and schema authors on this issue.

[Definition:]  A quantifier is one of ?, *, +, {n,m} or {n,}, which have the meanings defined in the table above.

[Definition:]  An atom is either a normal character, a character class, or a parenthesized regular expression.

For all normal characters c, character classes C, and regular expressions S, valid atoms R are: Denoting the set of strings L(R) containing:
c the single string consisting only of c
C all strings in L(C)
(S) all strings in L(S)

[Definition:]  A metacharacter is either ., \, ?, *, +, {, } (, ), [ or ]. These characters have special meanings in regular expressions, but can be escaped to form atoms that denote the sets of strings containing only themselves, i.e., an escaped metacharacter behaves like a normal character.

[Definition:]  A normal character is any XML character that is not a metacharacter. In regular expressions, a normal character is an atom that denotes the singleton set of strings containing only itself.

Note that a normal character can be represented either as itself, or with a character reference.

E.1 Character Classes

[Definition:]  A character class is an atom R that identifies a set of characters C(R). The set of strings L(R) denoted by a character class R contains one single-character string "c" for each character c in C(R).

A character class is either a character class escape or a character class expression.

[Definition:]  A character class expression is a character group surrounded by [ and ] characters. For all character groups G, [G] is a valid character class expression, identifying the set of characters C([G]) = C(G).

[Definition:]  A character group is either positive character group, a negative character group, or a character class subtraction.

[Definition:]   A positive character group consists of one or more character ranges or character class escapes, concatenated together. A positive character group identifies the set of characters containing all of the characters in all of the sets identified by its constituent ranges or escapes.

For all character ranges R, all character class escapes E, and all positive character groups P, valid positive character groups G are: Identifying the set of characters C(G) containing:
R all characters in C(R).
E all characters in C(E).
RP all characters in C(R) and all characters in C(P).
EP all characters in C(E) and all characters in C(P).

[Definition:]   A negative character group is a positive character group preceded by the ^ character. For all positive character groups P, ^P is a valid negative character group, and C(^P) contains all XML characters that are not in C(P).

[Definition:]  A character class subtraction is a character class expression subtracted from a positive character group or negative character group, using the - character.

For any positive character group or negative character group G, and any character class expression C, G-C is a valid character class subtraction, identifying the set of all characters in C(G) that are not also in C(C).

[Definition:]  A character range R identifies a set of characters C(R) containing all XML characters with Unicode code points in a specified range.

A single XML character is a character range that identifies the set of characters containing only itself. All XML chacters are valid character ranges, except as follows:

A character range may also be written in the form s-e, identifying the set that contains all XML characters with Unicode code points greater than or equal to the code point of s, but not greater than the code point of e.

s-e is a valid character range iff:

NOTE: The code point of a single character escape is the code point of the single character in the set of characters that it identifies.

E.1.1 Character Class Escapes

[Definition:]   A character class escape is a short sequence of characters that identifies predefined character class. The valid character class escapes include the single character escapes, the multi-character escapes, and the category escapes.

[Definition:]  A single character escape identifies a set containing a only one character -- usually because that character is difficult or impossible to write directly into a regular expression.

The valid single character escapes are: Identifying the set of characters C(R) containing:
\n the newline character (&#xA;)
\r the return character (&#xD;)
\t the tab character (&#x9;)
\\ \
\. .
\- -
\^ ^
\? ?
\* *
\+ +
\{ {
\} }
\( (
\) )
\[ [
\] ]

[Definition:]  The Unicode Standard [Unicode] defines a number of character properties and provides mappings from code points to specific character properties. The set containing of all characters that have property X, may be identified with a category escape \p{X}. The compliment of this set may be specified with the category escape \P{X}. ([\P{X}] = [^\p{X}]).

NOTE: The syntax \p{X} is the same as that used in [Perl 5.6].

The following table specifies the main character properties (for more information, see Chapter 4 of [Unicode]).

Category Property Meaning
Letters L All Letters
Lu Uppercase
Ll Lowercase
Lt Titlecase
Lm Modifier
Lo Other
 
Marks M All Marks
Mn Non-Spacing
Mc Spacing Combining
Me Enclosing
 
Numbers N All Numbers
Nd Decimal Digit
Nl Letter
No Other
 
Punctuation P All Punctuation
Pc Connector
Pd Dash
Ps Open
Pe Close
Pi Initial quote (may behave like Ps or Pe depending on usage)
Pf Final quote (may behave like Ps or Pe depending on usage)
Po Other
 
Separators Z All Separators
Zs Space
Zl Line
Zp Paragraph
 
Symbols S All Symbols
Sm Math
Sc Currency
Sk Modifier
So Other
 
Other C All Others
Cc Control
Cf Format
Cs Surrogate
Co Private Use
Cn Not Assigned

[Definition:]  The Unicode Standard [Unicode] groups code points into a number of blocks such as Basic Latin (i.e., ASCII), Latin-1 Suppliment, Hangul Jamo, CJK Compatibility, etc. The set containing of all characters that have block name X (with all whitespace stripped out), may be identified with a block escape \p{IsX}. The compliment of this set may be specified with the block escape \P{IsX}. ([\P{IsX}] = [^\p{IsX}]).

NOTE: The syntax \p{IsX} is the same as that used in [Perl 5.6].

For example, the block escape for identifying the ASCII characters is \p{IsBasicLatin}.

[Definition:]  A multi-character escape provides a simple way to identify a commonly used set of characters:

Character sequence Equivalent character class
. [^\n\r]
\s [&#x20;\t\n\r]
\S [^\s]
\i [\p{L}\p{Nl}:_]
\I [^\i]
\c the set of characters matched by NameChar
\C [^\c]
\d \p{Nd}
\D [^\d]
\w [&#x0000;-&#xFFFF;]-[\p{P}\p{S}\p{C}] (all characters except the set of "punctuation", "separator" and "control" characters)
\W [^\w]

F References

F.1 Normative

Clinger, WD (1990)
William D Clinger. How to Read Floating Point Numbers Accurately. In Proceedings of Conference on Programming Language Design and Implementation, pages 92-101. Available at: ftp://ftp.ccs.neu.edu/pub/people/will/howtoread.ps
IEEE 754-1985
IEEE. IEEE Standard for Binary Floating-Point Arithmetic. See http://standards.ieee.org/reading/ieee/std_public/description/busarch/754-1985_desc.html
ISO 10646
ISO (International Organization for Standardization). ISO/IEC 10646-1993 (E). Information technology --- Universal Multiple-Octet Coded Character Set (UCS) --- Part 1: Architecture and Basic Multilingual Plane. [Geneva]: International Organization for Standardization, 1993 (plus amendments AM 1 through AM 7).
Namespaces in XML
World Wide Web Consortium. Namespaces in XML. Available at: http://www.w3.org/TR/REC-xml-names/
RFC 1766
H. Alvestrand, ed. RFC 1766: Tags for the Identification of Languages 1995. Available at: http://www.ietf.org/rfc/rfc1766.txt
RFC 2045
N. Freed and N. Borenstein. RFC 2045: Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies. 1996 Available at: http://www.ietf.org/rfc/rfc2045.txt
RFC 2396
Tim Berners-Lee, et. al. RFC 2396: Uniform Resource Identifiers (URI): Generic Syntax.. 1998 Available at: http://www.ietf.org/rfc/rfc2396.txt
Unicode
The Unicode Consortium. The Unicode Standard, Version 2.0. Reading, Mass.: Addison-Wesley Developers Press, 1996.
Unicode Database
The Unicode Consortium. The Unicode Character Database. Available at: ftp://ftp.unicode.org/Public/3.0-Update/UnicodeCharacterDatabase-3.0.0.html
XML 1.0 Recommendation
World Wide Web Consortium. Extensible Markup Language (XML) 1.0. Available at: http://www.w3.org/TR/REC-xml
XML Information Set
World Wide Web Consortium. XML Information Set (public WD) Available at: http://www.w3.org/TR/xml-infoset
XML Schema Part 1: Structures
XML Schema Part 1: Structures. Available at: http://www.w3.org/TR/2000/WD-xmlschema-1-20000407/
XML Schema Requirements
XML Schema Requirements. Available at: http://www.w3.org/TR/NOTE-xml-schema-req

F.2 Non-normative

Gay, DM (1990)
David M. Gay. Correctly Rounded Binary-Decimal and Decimal-Binary Conversions. AT&T Bell Laboratories Numerical Analysis Manuscript 90-10, November 1990. Available at: http://cm.bell-labs.com/cm/cs/doc/90/4-10.ps.gz
ISO 11404
ISO (International Organization for Standardization). Language-independent Datatypes. See http://www.iso.ch/cate/d19346.html
ISO 8601
ISO (International Organization for Standardization). Representations of dates and times, 1988-06-15. Available at: http://www.iso.ch/markete/8601.pdf
ISO 8601 Draft Revision
ISO (International Organization for Standardization). Representations of dates and times, draft revision, 1998.
Perl
The Perl Programming Language. See http://www.perl.com
Perl 5.6
The Perl Programming Language, Version 5.6. See http://www.perl.com/language/misc/ann58/index.html
RDF Schema
World Wide Web Consortium. RDF Schema Specification. Available at: http://www.w3.org/TR/rdf-schema/
SQL
ISO (International Organization for Standardization). ISO/IEC 9075-2:1999, Information technology --- Database languages --- SQL --- Part 2: Foundation (SQL/Foundation). [Geneva]: International Organization for Standardization, 1999. See http://www.iso.ch/cate/d26197.html
Unicode Regular Expression Guidelines
Mark Davis. Unicode Regular Expression Guidelines, 1988. Available at: http://www.unicode.org/unicode/reports/tr18/
XSL
World Wide Web Consortium. Extensible Stylesheet Language (XSL). Available at: http://www.w3.org/TR/xsl/

G Acknowledgments (non-normative)

The following have contributed material to this draft:

The editors acknowledge the members of the XML Schema Working Group, the members of other W3C Working Groups, and industry experts in other forums who have contributed directly or indirectly to the process or content of creating this document. The Working Group is particularly grateful to Lotus Development Corp. and IBM for providing teleconferencing facilities.

The current members of the XML Schema Working Group are:

Jim Barnette, Defense Information Systems Agency (DISA); David Beech, Oracle Corp.; Paul V. Biron, Health Level Seven; Don Box, DevelopMentor; Allen Brown, Microsoft; Lee Buck, Extensibility; Charles E. Campbell, Informix; Peter Chen, Bootstrap Alliance and LSU; David Cleary, Progress Software; Dan Connolly, W3C (staff contact); Roger L. Costello, MITRE; Ugo Corda, Xerox; Andrew Eisenberg, Progress Software; David Ezell, Hewlett Packard Company; David Fallside, IBM; Matthew Fuchs, Commerce One; Andrew Goodchild, Distributed Systems Technology Centre (DSTC Pty Ltd); Paul Grosso, ArborText, Inc; Martin Gudgin, DevelopMentor; Dave Hollander, CommerceNet (co-chair); Mary Holstege, Calico Commerce; Jane Hunter, Distributed Systems Technology Centre (DSTC Pty Ltd); Rick Jelliffe, Academia Sinica; Andrew Layman, Microsoft; Dmitry Lenkov, Hewlett Packard Company; Eve Maler, Sun Microsystems; Ashok Malhotra, IBM; Murray Maloney, Commerce One; John McCarthy, Lawrence Berkeley National Laboratory; Noah Mendelsohn, Lotus Development Corporation; Don Mullen, Extensibility; Frank Olken, Lawrence Berkeley National Laboratory; Dave Peterson, Graphic Communications Association; Mark Reinhold, Sun Microsystems; Jonathan Robie, Software AG; John C. Schneider, MITRE; Lew Shannon, NCR; C. M. Sperberg-McQueen, W3C (co-chair); Bob Streich, Calico Commerce; Henry S. Thompson, University of Edinburgh; Matt Timmermans, Microstar; Jim Trezzo, Oracle Corp.; Steph Tryphonas, Microstar; Mark Tucker, Health Level Seven; Asir S. Vedamuthu, webMethods, Inc; Priscilla Walmsley, XMLSolutions; Norm Walsh, ArborText, Inc; Aki Yoshida, SAP AG

The XML Schema Working Group has benefited in its work from the participation and contributions of a number of people not currently members of the Working Group, including in particular those named below. Affiliations given are those current at the time of their work with the WG.

Paula Angerstein, Vignette Corporation; Gabe Beged-Dov, Rogue Wave Software; Greg Bumgardner, Rogue Wave Software; Dean Burson, Lotus Development Corporation; Rob Ellman, Calico Commerce; George Feinberg, Object Design; Charles Frankston, Microsoft; Ernesto Guerrieri, Inso; Michael Hyman, Microsoft; Renato Iannella, Distributed Systems Technology Centre (DSTC Pty Ltd); Dianne Kennedy, Graphic Communications Association; Janet Koenig, Sun Microsystems; Setrag Khoshafian, Technology Deployment International (TDI); Ara Kullukian, Technology Deployment International (TDI); Murata Makoto, Xerox; Chris Olds, Wall Data; Shriram Revankar, Xerox; William Shea, Merrill Lynch; Ralph Swick, W3C; Tony Stewart, Rivcom

H Revisions from Previous Draft

  1. 2000-03-01: pvb: fixed inconsistency in specification of length related facets for binary type: all are now specified in octets
  2. 2000-03-02: pvb: removed paragraph from section describing the ordered facet/property which talked about the possibility of multiple order relations on a value-space
  3. 2000-03-02: pvb: table in appendix C.1 is now auto-generated from appinfo supplied info w/i the schema for builtins (builtins.xsd)
  4. 2000-03-03: pvb: changed non-norm reference to SQL to be the actual ISO bibref
  5. 2000-03-04: pvb: fixed bug in defn of regex, to allow for the empty regex
  6. 2000-03-08: am: changed date and time datatypes completely (yet again).
  7. 2000-03-10: pvb: added separate appendix for schema for builtin types
  8. 2000-03-10: pvb: changed example for precision facet (old one didn't apply)
  9. 2000-03-10: pvb: change case on facets and type names to be Pascal-like: effected facets minlength and maxlength; and datatypes uri-reference, non-positive-integer, non-negative-integer, negitive-integer, positive-integer, unsigned-long, unsigned-int, unsigned-short, unsigned-byte.
  10. 2000-03-10: pvb: fixed example for enumeration facet (to use recurringDate instead of date for its basetype.
  11. 2000-03-14: am: updated date/time types (yet again): changed recurringInstant into recurringDuration, made timeInstant derived from recurringDuration instead of primitive, added timePeriod, month, year, century, recurringDate, and recurringDay
  12. 2000-03-14: am: modified description of lists of atomic types that allow whitespace in their literals so that it is clearer
  13. 2000-03-15: pvb: added text (written by Mark Reinhold) to float & double describing the "best approximation" required for mapping from lexical to value space
  14. 2000-03-15: pvb: cleaned up description of lexical reps for numeric types
  15. 2000-03-15: pvb: added some explanatory text to the beginning of sections 4 and 5
  16. 2000-03-15: pvb: made it clear (in section 4.1) that a datatype's facets consist of the facets directly specified in the defn as well as the set inherited from its basetype
  17. 2000-03-15: pvb: cleaned up datatype-valid "validity constribution".
  18. 2000-03-15: pvb: added facet-valid "validity contributions" for each facet in section 4 (some just stubs at this point)
  19. 2000-03-15: pvb: moved bibl for clinger1990 from non-normative to normative, since we are now requiring his "best approximation" for float/double
  20. 2000-03-16: am: Changed section 2.5.1.2 List Datatypes
  21. 2000-03-16: am: Changed section 5.1.2 List Datatype
  22. 2000-03-16: am: Changed section 5.2.1 Length example
  23. 2000-03-16: am: Fixed sections 5.1.13 and 5.2.14
  24. 2000-03-16: am: Changed section on lex rep for unsignedLong, unsignedInt, unsignedShort and unsignedByte to remove optional sign (after all, they are "unsigned"). Also fixed examples.
  25. 2000-03-16: am: Changed lex rep section for timePeriod.
  26. 2000-03-16: am: Changed section on timePeriod.
  27. 2000-03-16: am: Added wording to 4.2.4 and 4.2.5
  28. 2000-03-16: am: Removed ednotes from section 4 sections on min/max inclusive/exclusive. dates and times compare chronologically.
  29. 2000-03-16: pvb: fixed several problems with the regex appx: a) a branch is 0 or more (not 1 or more) (empty regex matches the empty string); b) added numeric quantifiers ({n,m}, etc.); c) fixed bug if meaning of S*; d) added { and } to list of metacharacters and "single character escapes"; e) noted that a "normal character" can be represented as a character reference; f) added syntax for identifying blocks (e.g., \p{IsBasicLatin})
  30. 2000-03-16: pvb: make QName into a primitive, with value space the set of tuples {namespace URI, localPart}. Semantically, this is how it should be defined, but it kind of breaks our type system: QName is now clearly not an atomic type (it is an aggregate defined in terms of two other existing types), which means that it shouldn't be primitive and should be derived, but we don't have type generators...oh, well.
  31. 2000-03-16: pvb: uriReference lexical space now specified as strings matching the URI-reference production from RFC 2396...still need to generate a regex corresponding to that production
  32. 2000-03-17: pvb: moved all COS constraints into the appropriate subsection of section 4 "datatype components"
  33. 2000-03-17: pvb: clarified statement in enumeration facet that it imposes no order on the value space constructed
  34. 2000-03-17: pvb: clarified precision/scale to be a maximum number of digits
  35. 2000-03-17: pvb: completed most of the facet-valid "validity contributions" which began as just stubs, still a few more to go
  36. 2000-03-17: pvb: explicitly defined the notion of an order relation (which was mentioned, but not defined)
  37. 2000-03-17: pvb: corrected defn of string to state that the order relation (and not the ordered property) as unicode code point
  38. 2000-03-17: pvb: clarified length, minLength and maxLength facets; namely, that string is measured in code points (rather than the ambiguous "character"), that binary is measured in octets of the binary data (not the lexical/encoded data), and specified meaning of these facets for lists (only length was specified before)
  39. 2000-03-17: pvb: added defns for "constraint on schema", "schema representation constraint" and "validation contribution" (largely stolen from structures) to terminology section
  40. 2000-03-17: pvb: replaced Conformance section with a subset of the equivalent section from structures
  41. 2000-03-17: pvb: added schema representation constraints for multiple patterns and enumerations
  42. 2000-03-17: pvb: explicitly defined order relations for float, double, timeDuration and recurringDuration
  43. 2000-04-03: pvb: corrected NOTE on ENTITY datatype to say 'defined in a DTD' rather than a schema
  44. 2000-04-03: pvb: fixed presentation of table in "Constraint on Schemas: applicable facets"
  45. 2000-04-03: pvb: replaced empty validity contributions on encoding, duration and period facet components with NOTEs that they don't participate in validation
  46. 2000-04-03: pvb: removed "open issues" appendix
  47. 2000-04-03: pvb: removed all terms in the "terminology" section which weren't used...also made all *uses* of the remaining terms into links to their definitions
  48. 2000-04-03: pvb: styled constraints on schema, etc. in tables, with the table header color coded to indicate the type of constraint
  49. 2000-04-03: pvb: modified section on Equality, to note that equality is defined (to be not equal) across value spaces not related via restriction.
  50. 2000-04-03: pvb: incorporated new {schema,dtd} for datatypes
  51. 2000-04-04: pvb: replaced ednotes in 5.1.2 with some simple expository text, probably will need to be expanded on before CR
  52. 2000-04-04: pvb: rewrote description of truncated forms of timeDuration, so that it was more explicit about what is allowed