XML Schema Part 2: Datatypes Second Edition (original) (raw)

1 Introduction

1.1 Purpose

The [XML 1.0 (Second Edition)] 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.

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 and Java primitive datatypes, 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).

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 ·facet·s 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:

• defined axiomatically from fundamental notions (intensional definition) [see ·primitive·]
• enumerated outright (extensional definition) [see ·enumeration·]
• defined by restricting the ·value space· of an already defined datatype to a particular subset with a given set of properties [see ·derived·]
• defined as a combination of values from one or more already defined·value space·(s) by a specific construction procedure [see ·list· and ·union·]

·value space·s have certain properties. For example, they always have the property of ·cardinality·, some definition of _equality_and might be ·ordered·, by which individual values within the ·value space· can be compared to one another. The properties of ·value space·s that are recognized by this specification are defined inFundamental facets (§2.4.1).

2.3 Lexical space

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

[Definition:] Alexical space is the set of valid _literals_for a datatype.

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.

Note: The literals in the ·lexical space·s defined in this specification have the following characteristics:

Interoperability:

The number of literals for each value has been kept small; for many datatypes there is a one-to-one mapping between literals and values. This makes it easy to exchange the values between different systems. In many cases, conversion from locale-dependent representations will be required on both the originator and the recipient side, both for computer processing and for interaction with humans.

Basic readability:

Textual, rather than binary, literals are used. This makes hand editing, debugging, and similar activities possible.

Ease of parsing and serializing:

Where possible, literals correspond to those found in common programming languages and libraries.

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.

2.5 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 vs. union datatypes

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

• [Definition:] Atomic datatypes are those having values which are regarded by this specification as being indivisible.
• [Definition:] Listdatatypes are those having values each of which consists of a finite-length (possibly empty) sequence of values of an·atomic· datatype.
• [Definition:] Uniondatatypes are those whose ·value space·s and·lexical space·s are the union of the ·value space·s and·lexical space·s of one or more other datatypes.

For example, a single token which ·match·esNmtoken from[XML 1.0 (Second Edition)] 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 can 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 space-separated sequence of literals of the·atomic· datatype of the items in the·list·.

[Definition:] The ·atomic· or ·union·datatype that participates in the definition of a ·list· datatype is known as the itemType of that ·list· datatype.

8 10.5 12

A ·list· datatype can be ·derived·from an ·atomic· datatype whose·lexical space· allows space (such as stringor anyURI)or a·union· datatype any of whose {member type definitions}'s·lexical space· allows space. In such a case, regardless of the input, list items will be separated at space boundaries.

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 facet·s apply:

• ·length·
• ·maxLength·
• ·minLength·
• ·enumeration·
• ·pattern·
• ·whiteSpace·

For each of ·length·, ·maxLength·and ·minLength·, the unit of length is measured in number of list items. The value of ·whiteSpace·is fixed to the value collapse.

For ·list· datatypes the ·lexical space·is composed of space-separated literals of its ·itemType·. Hence, any·pattern· specified when a new datatype is·derived· from a ·list· datatype is matched against each literal of the ·list· datatype and not against the literals of the datatype that serves as its·itemType·.

<xs:simpleType name='myList'> <xs:list itemType='xs:integer'/> <xs:simpleType name='myRestrictedList'> <xs:restriction base='myList'> <xs:pattern value='123 (\d+\s)*456'/> 123 456 123 987 456 123 987 567 456

The canonical-lexical-representation for the·list· datatype is defined as the lexical form in which each item in the ·list· has the canonical lexical representation of its ·itemType·.

2.5.1.3 Union datatypes

The ·value space· and ·lexical space·of a ·union· datatype are the union of the·value space·s and ·lexical space·s of its ·memberTypes·.·union· datatypes are always ·derived·. Currently, there are no ·built-in· ·union·datatypes.

A prototypical example of a ·union· type is themaxOccurs attribute on theelement elementin XML Schema itself: it is a union of nonNegativeInteger and an enumeration with the single member, the string "unbounded", as shown below.

Any number (greater than 1) of ·atomic· or ·list· ·datatype·s can participate in a ·union· type.

[Definition:] The datatypes that participate in the definition of a ·union· datatype are known as thememberTypes of that ·union· datatype.

The order in which the ·memberTypes· are specified in the definition (that is, the order of the children of the element, or the order of the QNames in the _memberTypes_attribute) is significant. During validation, an element or attribute's value is validated against the·memberTypes· in the order in which they appear in the definition until a match is found. The evaluation order can be overridden with the use of xsi:type.

For example, given the definition below, the first instance of the element validates correctly as an integer (§3.3.13), the second and third asstring (§3.2.1).

<xsd:element name='size'> xsd:simpleType xsd:union xsd:simpleType <xsd:restriction base='integer'/> xsd:simpleType <xsd:restriction base='string'/>

1 large 1

The canonical-lexical-representation for a·union· datatype is defined as the lexical form in which the values have the canonical lexical representation of the appropriate ·memberTypes·.

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. Furthermore, a datatype which is a ·union· in this specification need not be a "union" datatype in any programming language used to implement this specification.

2.5.2 Primitive vs. derived datatypes

Next, we distinguish between ·primitive· and·derived· datatypes.

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

For example, in this specification, float is a well-defined mathematical concept that cannot be defined in terms of other datatypes, while a integer is a special case of the more general datatypedecimal.

[Definition:] The simple ur-type definition is a special restriction of theur-type definitionwhose name is anySimpleType in the XML Schema namespace.anySimpleType can be considered as the ·base type· of all ·primitive·datatypes.anySimpleType is considered to have an unconstrained lexical space and a·value space· consisting of the union of the·value space·s of all the·primitive·datatypes and the set of all lists of all members of the·value space·s of all the·primitive· datatypes.

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·.

In the example above, integer is ·derived·from decimal.

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.

As described in more detail in XML Representation of Simple Type Definition Schema Components (§4.1.2), each ·user-derived· datatype ·must·be defined in terms of another datatype in one of three ways: 1) by assigning·constraining facet·s which serve to restrict the·value space· of the ·user-derived·datatype to a subset of that of the ·base type·; 2) by creating a ·list· datatype whose ·value space·consists of finite-length sequences of values of its·itemType·; or 3) by creating a ·union·datatype whose ·value space· consists of the union of the·value space·s of its ·memberTypes·.

2.5.2.1 Derived by restriction

[Definition:] A datatype is said to be·derived· by restriction from another datatype when values for zero or more ·constraining facet·s are specified that serve to constrain its ·value space· and/or its·lexical space· to a subset of those of its·base type·.

[Definition:] Every datatype that is ·derived· by restrictionis defined in terms of an existing datatype, referred to as itsbase type. base types can be either·primitive· or ·derived·.

2.5.2.2 Derived by list

A ·list· datatype can be ·derived·from another datatype (its ·itemType·) by creating a ·value space· that consists of a finite-length sequence of values of its ·itemType·.

2.5.3 Built-in vs. user-derived datatypes

• [Definition:] Built-indatatypes are those which are defined in this specification, and can be either ·primitive· or·derived·;
• [Definition:] User-derived datatypes are those ·derived·datatypes that are defined by individual schema designers.

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

Each built-in datatype in this specification (both·primitive· and·derived·) can be uniquely addressed via a URI Reference constructed as follows:

1. the base URI is the URI of the XML Schema namespace
2. the fragment identifier is the name of the datatype

For example, to address the int datatype, the URI is:

• http://www.w3.org/2001/XMLSchema#int

Additionally, each facet definition element can be uniquely addressed via a URI constructed as follows:

1. the base URI is the URI of the XML Schema namespace
2. the fragment identifier is the name of the facet

For example, to address the maxInclusive facet, the URI is:

• http://www.w3.org/2001/XMLSchema#maxInclusive

Additionally, each facet usage in a built-in datatype definition can be uniquely addressed via a URI constructed as follows:

1. the base URI is the URI of the XML Schema namespace
2. the fragment identifier is the name of the datatype, followed by a period (".") followed by the name of the facet

For example, to address the usage of the maxInclusive facet in the definition of int, the URI is:

• http://www.w3.org/2001/XMLSchema#int.maxInclusive

3.1 Namespace considerations

The ·built-in· datatypes defined by this specification are designed to be used with the XML Schema definition language as well as other XML specifications. To facilitate usage within the XML Schema definition language, the ·built-in·datatypes in this specification have the namespace name:

• http://www.w3.org/2001/XMLSchema

To facilitate usage in specifications other than the XML Schema definition language, such as those that do not want to know anything about aspects of the XML Schema definition language other than the datatypes, each ·built-in·datatype is also defined in the namespace whose URI is:

• http://www.w3.org/2001/XMLSchema-datatypes

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]).

3.2 Primitive datatypes

3.2.1 string
3.2.2 boolean
3.2.3 decimal
3.2.4 float
3.2.5 double
3.2.6 duration
3.2.7 dateTime
3.2.8 time
3.2.9 date
3.2.10 gYearMonth
3.2.11 gYear
3.2.12 gMonthDay
3.2.13 gDay
3.2.14 gMonth
3.2.15 hexBinary
3.2.16 base64Binary
3.2.17 anyURI
3.2.18 QName
3.2.19 NOTATION

The ·primitive· datatypes defined by this specification are described below. For each datatype, the·value space· and ·lexical space·are defined, ·constraining facet·s which apply to the datatype are listed and any datatypes ·derived·from this 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 ofcharacters (as defined in[XML 1.0 (Second Edition)]) that ·match· theChar production from [XML 1.0 (Second Edition)]. A character is an atomic unit of communication; it is not further specified except to note that everycharacter has a corresponding Universal Character Set code point, which is an integer.

Note: Many human languages have writing systems that require child elements for control of aspects such as bidirectional formating or ruby annotation (see [Ruby] and Section 8.2.4Overriding the bidirectional algorithm: the BDO element of [HTML 4.01]). Thus, string, as a simple type that can contain only characters but not child elements, is often not suitable for representing text. In such situations, a complex type that allows mixed content should be considered. For more information, see Section 5.5Any Element, Any Attributeof [XML Schema Language: Part 0 Primer].

Note: As noted in ordered, the fact that this specification does not specify an ·order-relation· for ·string·does not preclude other applications from treating strings as being ordered.

3.2.3 decimal

[Definition:] decimalrepresents a subset of the real numbers, which can be represented by decimal numerals. The ·value space· of decimalis the set of numbers that can be obtained by multiplying an integer by a non-positive power of ten, i.e., expressible as _i × 10^-n_where i and n are integers and n >= 0. Precision is not reflected in this value space; the number 2.0 is not distinct from the number 2.00. The ·order-relation· on decimalis the order relation on real numbers, restricted to this subset.

Note: All ·minimally conforming· processors ·must·support decimal numbers with a minimum of 18 decimal digits (i.e., with a·totalDigits· of 18). However,·minimally conforming· processors ·may·set an application-defined limit on the maximum number of decimal digits they are prepared to support, in which case that application-defined maximum number ·must· be clearly documented.

3.2.4 float

[Definition:] floatis patterned after the IEEE single-precision 32-bit floating point type[IEEE 754-1985]. The basic ·value space· offloat 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 three_special values_: positive and negative infinity and not-a-number (NaN). The ·order-relation· on floatis: x < y iff y - x is positive for x and y in the value space. Positive infinity is greater than all other non-NaN values. NaN equals itself but is ·incomparable· with (neither greater than nor less than) any other value in the ·value space·.

Note: "Equality" in this Recommendation is defined to be "identity" (i.e., values that are identical in the ·value space· are equal and vice versa). Identity must be used for the few operations that are defined in this Recommendation. Applications using any of the datatypes defined in this Recommendation may use different definitions of equality for computational purposes; [IEEE 754-1985]-based computation systems are examples. Nothing in this Recommendation should be construed as requiring that such applications use identity as their equality relationship when computing.

Any value ·incomparable· with the value used for the four bounding facets (·minInclusive·, ·maxInclusive·,·minExclusive·, and ·maxExclusive·) will be excluded from the resulting restricted ·value space·. In particular, when "NaN" is used as a facet value for a bounding facet, since no otherfloat values are ·comparable· with it, the result is a ·value space·either having NaN as its only member (the inclusive cases) or that is empty (the exclusive cases). If any other value is used for a bounding facet, NaN will be excluded from the resulting restricted ·value space·; to add NaN back in requires union with the NaN-only space.

This datatype differs from that of [IEEE 754-1985] in that there is only one NaN and only one zero. This makes the equality and ordering of values in the data space differ from that of [IEEE 754-1985] only in that for schema purposes NaN = NaN.

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 in the sense defined by[Clinger, WD (1990)]; if d is exactly halfway between two such values then the even value is chosen.

3.2.4.1 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 forinteger 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 infinity and not-a-number have lexical representationsINF, -INF andNaN, respectively. Lexical representations for zero may take a positive or negative sign.

For example, -1E4, 1267.43233E12, 12.78e-2, 12 , -0, 0and INF are all legal literals for float.

3.2.4.2 Canonical representation

The canonical representation for float is defined by prohibiting certain options from theLexical representation (§3.2.4.1). Specifically, the exponent must be indicated by "E". Leading zeroes and the preceding optional "+" sign are prohibited in the exponent. If the exponent is zero, it must be indicated by "E0". For the mantissa, the preceding optional "+" sign is prohibited and the decimal point is required. Leading and trailing zeroes are prohibited subject to the following: number representations must be normalized such that there is a single digit which is non-zero to the left of the decimal point and at least a single digit to the right of the decimal point unless the value being represented is zero. The canonical representation for zero is 0.0E0.

3.2.5 double

[Definition:] The doubledatatype is patterned after the 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 three_special values_: positive and negative infinity and not-a-number (NaN). The ·order-relation· on doubleis: x < y iff y - x is positive for x and y in the value space. Positive infinity is greater than all other non-NaN values. NaN equals itself but is ·incomparable· with (neither greater than nor less than) any other value in the ·value space·.

Note: "Equality" in this Recommendation is defined to be "identity" (i.e., values that are identical in the ·value space· are equal and vice versa). Identity must be used for the few operations that are defined in this Recommendation. Applications using any of the datatypes defined in this Recommendation may use different definitions of equality for computational purposes; [IEEE 754-1985]-based computation systems are examples. Nothing in this Recommendation should be construed as requiring that such applications use identity as their equality relationship when computing.

Any value ·incomparable· with the value used for the four bounding facets (·minInclusive·, ·maxInclusive·,·minExclusive·, and ·maxExclusive·) will be excluded from the resulting restricted ·value space·. In particular, when "NaN" is used as a facet value for a bounding facet, since no otherdouble values are ·comparable· with it, the result is a ·value space·either having NaN as its only member (the inclusive cases) or that is empty (the exclusive cases). If any other value is used for a bounding facet, NaN will be excluded from the resulting restricted ·value space·; to add NaN back in requires union with the NaN-only space.

This datatype differs from that of [IEEE 754-1985] in that there is only one NaN and only one zero. This makes the equality and ordering of values in the data space differ from that of [IEEE 754-1985] only in that for schema purposes NaN = NaN.

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].

3.2.5.1 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 forinteger 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 infinity and not-a-number have lexical representationsINF, -INF andNaN, respectively. Lexical representations for zero may take a positive or negative sign.

For example, -1E4, 1267.43233E12, 12.78e-2, 12 , -0, 0and INFare all legal literals for double.

3.2.5.2 Canonical representation

The canonical representation for double is defined by prohibiting certain options from theLexical representation (§3.2.5.1). Specifically, the exponent must be indicated by "E". Leading zeroes and the preceding optional "+" sign are prohibited in the exponent. If the exponent is zero, it must be indicated by "E0". For the mantissa, the preceding optional "+" sign is prohibited and the decimal point is required. Leading and trailing zeroes are prohibited subject to the following: number representations must be normalized such that there is a single digit which is non-zero to the left of the decimal point and at least a single digit to the right of the decimal point unless the value being represented is zero. The canonical representation for zero is 0.0E0.

3.2.6 duration

[Definition:] duration represents a duration of time. The ·value space· of duration is a six-dimensional space where the coordinates designate the Gregorian year, month, day, hour, minute, and second components defined in § 5.5.3.2 of [ISO 8601], respectively. These components are ordered in their significance by their order of appearance i.e. as year, month, day, hour, minute, and second.

Note:

All

·minimally conforming· processors ·must·support year values with a minimum of 4 digits (i.e., YYYY) and a minimum fractional second precision of milliseconds or three decimal digits (i.e. s.sss). However,·minimally conforming· processors ·may·set an application-defined limit on the maximum number of digits they are prepared to support in these two cases, in which case that application-defined maximum number ·must· be clearly documented.

3.2.6.1 Lexical representation

The lexical representation for duration is the[ISO 8601] extended format P_n_Y_n_M_n_DT_n_H _n_M_n_S, where_n_Y represents the number of years, _n_M the number of months, _n_D the number of days, 'T' is the date/time separator, _n_H the number of hours,_n_M the number of minutes and _n_S the number of seconds. The number of seconds can include decimal digits to arbitrary precision.

The values of the Year, Month, Day, Hour and Minutes components are not restricted but allow an arbitrary unsigned integer, i.e., an integer that conforms to the pattern [0-9]+.. Similarly, the value of the Seconds component allows an arbitrary unsigned decimal. Following [ISO 8601], at least one digit must follow the decimal point if it appears. That is, the value of the Seconds component must conform to the pattern [0-9]+(\.[0-9]+)?. Thus, the lexical representation ofduration does not follow the alternative format of § 5.5.3.2.1 of [ISO 8601].

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. One could also indicate a duration of minus 120 days as:-P120D.

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

• 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 seconds part ·may· have a decimal fraction.
• The designator 'T' must be absent if and only if all of the time items are absent. The designator 'P' must always be present.

For example, P1347Y, P1347M and 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 Order relation on duration

In general, the ·order-relation· on durationis a partial order since there is no determinate relationship between certain durations such as one month (P1M) and 30 days (P30D). The ·order-relation·of two duration values x and_y_ is _x < y iff s+x < s+y_for each qualified dateTime _s_in the list below. These values for s cause the greatest deviations in the addition of dateTimes and durations. Addition of durations to time instants is defined in Adding durations to dateTimes (§E).

• 1696-09-01T00:00:00Z
• 1697-02-01T00:00:00Z
• 1903-03-01T00:00:00Z
• 1903-07-01T00:00:00Z

The following table shows the strongest relationship that can be determined between example durations. The symbol <> means that the order relation is indeterminate. Note that because of leap-seconds, a seconds field can vary from 59 to 60. However, because of the way that addition is defined inAdding durations to dateTimes (§E), they are still totally ordered.

| | Relation | | | | | | | | ---------- | ------------ | ------------ | ------------ | ------------ | ------------ | ----------- | | P1Y | > P364D | <> P365D | | <> P366D | < P367D** | | | P1M | > P27D** | <> P28D | <> P29D | <> P30D | <> P31D | < P32D** | | P5M | > P149D** | <> P150D | <> P151D | <> P152D | <> P153D | < P154D |

Implementations are free to optimize the computation of the ordering relationship. For example, the following table can be used to compare durations of a small number of months against days.

| | Months | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | ... | | | -------- | ------- | -- | -- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Days | Minimum | 28 | 59 | 89 | 120 | 150 | 181 | 212 | 242 | 273 | 303 | 334 | 365 | 393 | ... | | Maximum | 31 | 62 | 92 | 123 | 153 | 184 | 215 | 245 | 276 | 306 | 337 | 366 | 397 | ... | |

3.2.7 dateTime

[Definition:] dateTime values may be viewed as objects with integer-valued year, month, day, hour and minute properties, a decimal-valued second property, and a boolean timezoned property. Each such object also has one decimal-valued method or computed property, timeOnTimeline, whose value is always a decimal number; the values are dimensioned in seconds, the integer 0 is 0001-01-01T00:00:00 and the value of timeOnTimeline for other dateTimevalues is computed using the Gregorian algorithm as modified for leap-seconds. The timeOnTimeline values form two related "timelines", one for timezoned values and one for non-timezoned values. Each timeline is a copy of the ·value space· of decimal, with integers given units of seconds.

The ·value space· ofdateTime is closely related to the dates and times described in ISO 8601. For clarity, the text above specifies a particular origin point for the timeline. It should be noted, however, that schema processors need not expose the timeOnTimeline value to schema users, and there is no requirement that a timeline-based implementation use the particular origin described here in its internal representation. Other interpretations of the ·value space· which lead to the same results (i.e., are isomorphic) are of course acceptable.

All timezoned times are Coordinated Universal Time (UTC, sometimes called "Greenwich Mean Time"). Other timezones indicated in lexical representations are converted to UTC during conversion of literals to values. "Local" or untimezoned times are presumed to be the time in the timezone of some unspecified locality as prescribed by the appropriate legal authority; currently there are no legally prescribed timezones which are durations whose magnitude is greater than 14 hours. The value of each numeric-valued property (other than timeOnTimeline) is limited to the maximum value within the interval determined by the next-higher property. For example, the day value can never be 32, and cannot even be 29 for month 02 and year 2002 (February 2002).

Note:

The date and time datatypes described in this recommendation were inspired by

[ISO 8601]. '0001' is the lexical representation of the year 1 of the Common Era (1 CE, sometimes written "AD 1" or "1 AD"). There is no year 0, and '0000' is not a valid lexical representation. '-0001' is the lexical representation of the year 1 Before Common Era (1 BCE, sometimes written "1 BC").

Those using this (1.0) version of this Recommendation to represent negative years should be aware that the interpretation of lexical representations beginning with a '-' is likely to change in subsequent versions.

[ISO 8601]makes no mention of the year 0; in [ISO 8601:1998 Draft Revision]the form '0000' was disallowed and this recommendation disallows it as well. However, [ISO 8601:2000 Second Edition], which became available just as we were completing version 1.0, allows the form '0000', representing the year 1 BCE. A number of external commentators have also suggested that '0000' be allowed, as the lexical representation for 1 BCE, which is the normal usage in astronomical contexts. It is the intention of the XML Schema Working Group to allow '0000' as a lexical representation in thedateTime, date, gYear, andgYearMonth datatypes in a subsequent version of this Recommendation. '0000' will be the lexical representation of 1 BCE (which is a leap year), '-0001' will become the lexical representation of 2 BCE (not 1 BCE as in this (1.0) version), '-0002' of 3 BCE, etc.

Note: See the conformance note in (§3.2.6) which applies to this datatype as well.

3.2.7.1 Lexical representation

The ·lexical space· of dateTime consists of finite-length sequences of characters of the form:'-'? yyyy '-' mm '-' dd 'T' hh ':' mm ':' ss ('.' s+)? (zzzzzz)?, where

• '-'? yyyy is a four-or-more digit optionally negative-signed numeral that represents the year; if more than four digits, leading zeros are prohibited, and '0000' is prohibited (see the Note above (§3.2.7); also note that a plus sign is not permitted);
• the remaining '-'s are separators between parts of the date portion;
• the first mm is a two-digit numeral that represents the month;
• dd is a two-digit numeral that represents the day;
• 'T' is a separator indicating that time-of-day follows;
• hh is a two-digit numeral that represents the hour; '24' is permitted if the minutes and seconds represented are zero, and the dateTime value so represented is the first instant of the following day (the hour property of adateTime object in the ·value space· cannot have a value greater than 23);
• ':' is a separator between parts of the time-of-day portion;
• the second mm is a two-digit numeral that represents the minute;
• ss is a two-integer-digit numeral that represents the whole seconds;
• '.' s+ (if present) represents the fractional seconds;
• zzzzzz (if present) represents the timezone (as described below).

For example, 2002-10-10T12:00:00-05:00 (noon on 10 October 2002, Central Daylight Savings Time as well as Eastern Standard Time in the U.S.) is 2002-10-10T17:00:00Z, five hours later than 2002-10-10T12:00:00Z.

For further guidance on arithmetic with dateTimes and durations, see Adding durations to dateTimes (§E).

3.2.7.3 Timezones

Timezones are durations with (integer-valued) hour and minute properties (with the hour magnitude limited to at most 14, and the minute magnitude limited to at most 59, except that if the hour magnitude is 14, the minute value must be 0); they may be both positive or both negative.

The lexical representation of a timezone is a string of the form:(('+' | '-') hh ':' mm) | 'Z', where

• hh is a two-digit numeral (with leading zeros as required) that represents the hours,
• mm is a two-digit numeral that represents the minutes,
• '+' indicates a nonnegative duration,
• '-' indicates a nonpositive duration.

The mapping so defined is one-to-one, except that '+00:00', '-00:00', and 'Z' all represent the same zero-length duration timezone, UTC; 'Z' is its canonical representation.

When a timezone is added to a UTC dateTime, the result is the date and time "in that timezone". For example, 2002-10-10T12:00:00+05:00 is 2002-10-10T07:00:00Z and 2002-10-10T00:00:00+05:00 is 2002-10-09T19:00:00Z.

3.2.7.4 Order relation on dateTime

dateTime value objects on either timeline are totally ordered by their timeOnTimeline values; between the two timelines, dateTime value objects are ordered by their timeOnTimeline values when their timeOnTimeline values differ by more than fourteen hours, with those whose difference is a duration of 14 hours or less being ·incomparable·.

In general, the ·order-relation· on dateTimeis a partial order since there is no determinate relationship between certain instants. For example, there is no determinate ordering between (a) 2000-01-20T12:00:00 and (b) 2000-01-20T12:00:00Z. Based on timezones currently in use, (c) could vary from 2000-01-20T12:00:00+12:00 to 2000-01-20T12:00:00-13:00. It is, however, possible for this range to expand or contract in the future, based on local laws. Because of this, the following definition uses a somewhat broader range of indeterminate values: +14:00..-14:00.

The following definition uses the notation S[year] to represent the year field of S, S[month] to represent the month field, and so on. The notation (Q & "-14:00") means adding the timezone -14:00 to Q, where Q did not already have a timezone. This is a logical explanation of the process. Actual implementations are free to optimize as long as they produce the same results.

The ordering between two dateTimes P and Q is defined by the following algorithm:

A.Normalize P and Q. That is, if there is a timezone present, but it is not Z, convert it to Z using the addition operation defined inAdding durations to dateTimes (§E)

• Thus 2000-03-04T23:00:00+03:00 normalizes to 2000-03-04T20:00:00Z

B. If P and Q either both have a time zone or both do not have a time zone, compare P and Q field by field from the year field down to the second field, and return a result as soon as it can be determined. That is:

1. For each i in {year, month, day, hour, minute, second}
   1. If P[i] and Q[i] are both not specified, continue to the next i
   2. If P[i] is not specified and Q[i] is, or vice versa, stop and return P <> Q
   3. If P[i] < Q[i], stop and return P < Q
   4. If P[i] > Q[i], stop and return P > Q
2. Stop and return P = Q

C.Otherwise, if P contains a time zone and Q does not, compare as follows:

1. P < Q if P < (Q with time zone +14:00)
2. P > Q if P > (Q with time zone -14:00)
3. P <> Q otherwise, that is, if (Q with time zone +14:00) < P < (Q with time zone -14:00)

D. Otherwise, if P does not contain a time zone and Q does, compare as follows:

1. P < Q if (P with time zone -14:00) < Q.
2. P > Q if (P with time zone +14:00) > Q.
3. P <> Q otherwise, that is, if (P with time zone +14:00) < Q < (P with time zone -14:00)

Examples:

3.2.8 time

[Definition:] timerepresents 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]. Specifically, it is a set of zero-duration daily time instances.

Since the lexical representation allows an optional time zone indicator, time values are partially ordered because it may not be able to determine the order of two values one of which has a time zone and the other does not. The order relation ontime values is theOrder relation on dateTime (§3.2.7.4) using an arbitrary date. See alsoAdding durations to dateTimes (§E). Pairs of time values with or without time zone indicators are totally ordered.

Note: See the conformance note in (§3.2.6) which applies to the seconds part of this datatype as well.

3.2.9 date

[Definition:] The ·value space· of dateconsists of top-open intervals of exactly one day in length on the timelines ofdateTime, beginning on the beginning moment of each day (in each timezone), i.e. '00:00:00', up to but not including '24:00:00' (which is identical with '00:00:00' of the next day). For nontimezoned values, the top-open intervals disjointly cover the nontimezoned timeline, one per day. For timezoned values, the intervals begin at every minute and therefore overlap.

A "date object" is an object with year, month, and day properties just like those of dateTime objects, plus an optional _timezone-valued_timezone property. (As with values of dateTime timezones are a special case of durations.) Just as a dateTime object corresponds to a point on one of the timelines, a date object corresponds to an interval on one of the two timelines as just described.

Timezoned date values track the starting moment of their day, as determined by their timezone; said timezone is generally recoverable for canonical representations.[Definition:] The recoverable timezone is that duration which is the result of subtracting the first moment (or any moment) of the timezoneddate from the first moment (or the corresponding moment) UTC on the same date. ·recoverable timezone·s are always durations between '+12:00' and '-11:59'. This "timezone normalization" (which follows automatically from the definition of the date ·value space·) is explained more inLexical representation (§3.2.9.1).

For example: the first moment of 2002-10-10+13:00 is 2002-10-10T00:00:00+13, which is 2002-10-09T11:00:00Z, which is also the first moment of 2002-10-09-11:00. Therefore 2002-10-10+13:00 is 2002-10-09-11:00; they are the same interval.

Note: For most timezones, either the first moment or last moment of the day (adateTime value, always UTC) will have a date portion different from that of the date itself! However, noon of that date (the midpoint of the interval) in that (normalized) timezone will always have the same date portion as thedate itself, even when that noon point in time is normalized to UTC. For example, 2002-10-10-05:00 begins during 2002-10-09Z and 2002-10-10+05:00 ends during 2002-10-11Z, but noon of both 2002-10-10-05:00 and 2002-10-10+05:00 falls in the interval which is 2002-10-10Z.

Note: See the conformance note in (§3.2.6) which applies to the year part of this datatype as well.

3.2.9.1 Lexical representation

For the following discussion, let the "date portion" of a dateTimeor date object be an object similar to a dateTime ordate object, with similar year, month, and day properties, but no others, having the same value for these properties as the originaldateTime or date object.

The ·lexical space· of date consists of finite-length sequences of characters of the form:'-'? yyyy '-' mm '-' dd zzzzzz?where the date and optional timezone are represented exactly the same way as they are for dateTime. The first moment of the interval is that represented by:'-' yyyy '-' mm '-' dd 'T00:00:00' zzzzzz?and the least upper bound of the interval is the timeline point represented (noncanonically) by:'-' yyyy '-' mm '-' dd 'T24:00:00' zzzzzz?.

Note: The ·recoverable timezone· of a date will always be a duration between '+12:00' and '11:59'. Timezone lexical representations, as explained for dateTime, can range from '+14:00' to '-14:00'. The result is that literals of dates with very large or very negative timezones will map to a "normalized" date value with a·recoverable timezone· different from that represented in the original representation, and a matching difference of +/- 1 day in the date itself.

3.2.9.2 Canonical representation

Given a member of the date ·value space·, thedate portion of the canonical representation (the entire representation for nontimezoned values, and all but the timezone representation for timezoned values) is always the date portion of the dateTime canonical representation of the interval midpoint (the dateTime representation, truncated on the right to eliminate 'T' and all following characters). For timezoned values, append the canonical representation of the ·recoverable timezone·.

3.2.10 gYearMonth

[Definition:] gYearMonth represents a specific gregorian month in a specific gregorian year. The·value space· of gYearMonthis the set of Gregorian calendar months as defined in § 5.2.1 of[ISO 8601]. Specifically, it is a set of one-month long, non-periodic instances e.g. 1999-10 to represent the whole month of 1999-10, independent of how many days this month has.

Since the lexical representation allows an optional time zone indicator, gYearMonth values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. If gYearMonthvalues are considered as periods of time, the order relation ongYearMonth values is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See alsoAdding durations to dateTimes (§E). Pairs of gYearMonthvalues with or without time zone indicators are totally ordered.

Note: Because month/year combinations in one calendar only rarely correspond to month/year combinations in other calendars, values of this type are not, in general, convertible to simple values corresponding to month/year combinations in other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

Note: See the conformance note in (§3.2.6) which applies to the year part of this datatype as well.

3.2.11 gYear

[Definition:] gYear represents a gregorian calendar year. The ·value space· ofgYear is the set of Gregorian calendar years as defined in § 5.2.1 of [ISO 8601]. Specifically, it is a set of one-year long, non-periodic instances e.g. lexical 1999 to represent the whole year 1999, independent of how many months and days this year has.

Since the lexical representation allows an optional time zone indicator, gYear values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. IfgYear values are considered as periods of time, the order relation on gYear values is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See alsoAdding durations to dateTimes (§E). Pairs of gYear values with or without time zone indicators are totally ordered.

Note: Because years in one calendar only rarely correspond to years in other calendars, values of this type are not, in general, convertible to simple values corresponding to years in other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

Note: See the conformance note in (§3.2.6) which applies to the year part of this datatype as well.

3.2.12 gMonthDay

[Definition:] gMonthDay is a gregorian 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· ofgMonthDay is the set of calendar dates, as defined in § 3 of [ISO 8601]. Specifically, it is a set of one-day long, annually periodic instances.

Since the lexical representation allows an optional time zone indicator, gMonthDay values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. IfgMonthDay values are considered as periods of time, in an arbitrary leap year, the order relation on gMonthDay values is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See alsoAdding durations to dateTimes (§E). Pairs of gMonthDay values with or without time zone indicators are totally ordered.

Note: Because day/month combinations in one calendar only rarely correspond to day/month combinations in other calendars, values of this type do not, in general, have any straightforward or intuitive representation in terms of most other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

3.2.13 gDay

[Definition:] gDay is a gregorian 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 gDay is the space of a set of calendar dates as defined in § 3 of [ISO 8601]. Specifically, it is a set of one-day long, monthly periodic instances.

This datatype can be used to represent a specific day of the month. To say, for example, that I get my paycheck on the 15th of each month.

Since the lexical representation allows an optional time zone indicator, gDay values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. IfgDay values are considered as periods of time, in an arbitrary month that has 31 days, the order relation on gDay values is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See alsoAdding durations to dateTimes (§E). Pairs of gDayvalues with or without time zone indicators are totally ordered.

Note: Because days in one calendar only rarely correspond to days in other calendars, values of this type do not, in general, have any straightforward or intuitive representation in terms of most other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

3.2.14 gMonth

[Definition:] gMonth is a gregorian month that recurs every year. The ·value space·of gMonth is the space of a set of calendar months as defined in § 3 of [ISO 8601]. Specifically, it is a set of one-month long, yearly periodic instances.

This datatype can be used to represent a specific month. To say, for example, that Thanksgiving falls in the month of November.

Since the lexical representation allows an optional time zone indicator, gMonth values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. IfgMonth values are considered as periods of time, the order relation on gMonth is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See alsoAdding durations to dateTimes (§E). Pairs of gMonthvalues with or without time zone indicators are totally ordered.

Note: Because months in one calendar only rarely correspond to months in other calendars, values of this type do not, in general, have any straightforward or intuitive representation in terms of most other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

3.2.15 hexBinary

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

3.2.16 base64Binary

[Definition:] base64Binaryrepresents Base64-encoded arbitrary binary data. The ·value space· ofbase64Binary is the set of finite-length sequences of binary octets. For base64Binary data the entire binary stream is encoded using the Base64 Alphabet in[RFC 2045].

The lexical forms of base64Binary values are limited to the 65 characters of the Base64 Alphabet defined in [RFC 2045], i.e., a-z,A-Z, 0-9, the plus sign (+), the forward slash (/) and the equal sign (=), together with the characters defined in [XML 1.0 (Second Edition)] as white space. No other characters are allowed.

For compatibility with older mail gateways, [RFC 2045] suggests that base64 data should have lines limited to at most 76 characters in length. This line-length limitation is not mandated in the lexical forms of base64Binarydata and must not be enforced by XML Schema processors.

The lexical space of base64Binary is given by the following grammar (the notation is that used in [XML 1.0 (Second Edition)]); legal lexical forms must match the Base64Binary production.

`Base64Binary ::= ((B64S B64S B64S B64S)*
((B64S B64S B64S B64) |
(B64S B64S B16S '=') |
(B64S B04S '=' #x20? '=')))?

B64S ::= B64 #x20?

B16S ::= B16 #x20?

B04S ::= B04 #x20?

B04 ::= [AQgw]
B16 ::= [AEIMQUYcgkosw048]
B64 ::= [A-Za-z0-9+/]

`

Note that this grammar requires the number of non-whitespace characters in the lexical form to be a multiple of four, and for equals signs to appear only at the end of the lexical form; strings which do not meet these constraints are not legal lexical forms of base64Binary because they cannot successfully be decoded by base64 decoders.

Note: The above definition of the lexical space is more restrictive than that given in [RFC 2045] as regards whitespace -- this is not an issue in practice. Any string compatible with the RFC can occur in an element or attribute validated by this type, because the ·whiteSpace· facet of this type is fixed to collapse, which means that all leading and trailing whitespace will be stripped, and all internal whitespace collapsed to single space characters, before the above grammar is enforced.

The canonical lexical form of a base64Binary data value is the base64 encoding of the value which matches the Canonical-base64Binary production in the following grammar:

Canonical-base64Binary ::= (B64 B64 B64 B64)* ((B64 B64 B16 '=') | (B64 B04 '=='))?

Note: For some values the canonical form defined above does not conform to[RFC 2045], which requires breaking with linefeeds at appropriate intervals.

The length of a base64Binary value is the number of octets it contains. This may be calculated from the lexical form by removing whitespace and padding characters and performing the calculation shown in the pseudo-code below:

lex2 := killwhitespace(lexform) -- remove whitespace characters lex3 := strip_equals(lex2) -- strip padding characters at end length := floor (length(lex3) * 3 / 4) -- calculate length

Note on encoding: [RFC 2045] explicitly references US-ASCII encoding. However, decoding of base64Binary data in an XML entity is to be performed on the Unicode characters obtained after character encoding processing as specified by[XML 1.0 (Second Edition)]

3.2.17 anyURI

[Definition:] anyURI represents a Uniform Resource Identifier Reference (URI). An anyURI value can be absolute or relative, and may have an optional fragment identifier (i.e., it may be a URI Reference). This type should be used to specify the intention that the value fulfills the role of a URI as defined by [RFC 2396], as amended by[RFC 2732].

The mapping from anyURI values to URIs is as defined by the URI reference escaping procedure defined in Section 5.4 Locator Attributeof [XML Linking Language] (see also Section 8Character Encoding in URI Referencesof [Character Model]). This means that a wide range of internationalized resource identifiers can be specified when an anyURI is called for, and still be understood as URIs per [RFC 2396], as amended by [RFC 2732], where appropriate to identify resources.

Note: Section 5.4 Locator Attributeof [XML Linking Language] requires that relative URI references be absolutized as defined in [XML Base] before use. This is an XLink-specific requirement and is not appropriate for XML Schema, since neither the·lexical space· nor the ·value space·of the anyURI type are restricted to absolute URIs. Accordingly absolutization must not be performed by schema processors as part of schema validation.

Note: Each URI scheme imposes specialized syntax rules for URIs in that scheme, including restrictions on the syntax of allowed fragment identifiers. Because it is impractical for processors to check that a value is a context-appropriate URI reference, this specification follows the lead of [RFC 2396] (as amended by [RFC 2732]) in this matter: such rules and restrictions are not part of type validity and are not checked by ·minimally conforming· processors. Thus in practice the above definition imposes only very modest obligations on ·minimally conforming· processors.

3.2.17.1 Lexical representation

The ·lexical space· of anyURI is finite-length character sequences which, when the algorithm defined in Section 5.4 of [XML Linking Language] is applied to them, result in strings which are legal URIs according to [RFC 2396], as amended by[RFC 2732].

Note: Spaces are, in principle, allowed in the ·lexical space·of anyURI, however, their use is highly discouraged (unless they are encoded by %20).

3.2.19 NOTATION

[Definition:] NOTATIONrepresents the NOTATION attribute type from [XML 1.0 (Second Edition)]. The ·value space·of NOTATION is the set of QNames of notations declared in the current schema. The ·lexical space· of NOTATION is the set of all names of notationsdeclared in the current schema (in the form of QNames).

For compatibility (see Terminology (§1.4)) NOTATIONshould be used only on attributes and should only be used in schemas with no target namespace.

3.3 Derived datatypes

3.3.1 normalizedString
3.3.2 token
3.3.3 language
3.3.4 NMTOKEN
3.3.5 NMTOKENS
3.3.6 Name
3.3.7 NCName
3.3.8 ID
3.3.9 IDREF
3.3.10 IDREFS
3.3.11 ENTITY
3.3.12 ENTITIES
3.3.13 integer
3.3.14 nonPositiveInteger
3.3.15 negativeInteger
3.3.16 long
3.3.17 int
3.3.18 short
3.3.19 byte
3.3.20 nonNegativeInteger
3.3.21 unsignedLong
3.3.22 unsignedInt
3.3.23 unsignedShort
3.3.24 unsignedByte
3.3.25 positiveInteger

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 Simple Type Definition Schema Components (§4.1.2) and the complete definitions of the ·built-in· ·derived· datatypes are provided in Appendix ASchema for Datatype Definitions (normative) (§A).

3.3.1 normalizedString

[Definition:] normalizedStringrepresents white space normalized strings. The ·value space· of normalizedString is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters. The ·lexical space· of normalizedString is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters. The ·base type· of normalizedString is string.

3.3.2 token

[Definition:] tokenrepresents tokenized strings. The ·value space· of token is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters, that have no leading or trailing spaces (#x20) and that have no internal sequences of two or more spaces. The ·lexical space· of token is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters, that have no leading or trailing spaces (#x20) and that have no internal sequences of two or more spaces. The ·base type· of token is normalizedString.

3.3.3 language

[Definition:] languagerepresents natural language identifiers as defined by by [RFC 3066]. The ·value space· of language is the set of all strings that are valid language identifiers as defined[RFC 3066]. The ·lexical space· oflanguage is the set of all strings that conform to the pattern [a-zA-Z]{1,8}(-[a-zA-Z0-9]{1,8})*. The ·base type· of language is token.

3.3.5 NMTOKENS

[Definition:] NMTOKENSrepresents the NMTOKENS attribute type from [XML 1.0 (Second Edition)]. The ·value space·of NMTOKENS is the set of finite, non-zero-length sequences of·NMTOKEN·s. The ·lexical space·of NMTOKENS is the set of space-separated lists of tokens, of which each token is in the ·lexical space· ofNMTOKEN. The ·itemType· ofNMTOKENS is NMTOKEN.

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

3.3.7 NCName

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

3.3.10 IDREFS

[Definition:] IDREFS represents theIDREFS attribute type from[XML 1.0 (Second Edition)]. The ·value space· ofIDREFS is the set of finite, non-zero-length sequences ofIDREFs. The ·lexical space· of IDREFS is the set of space-separated lists of tokens, of which each token is in the·lexical space· of IDREF. The ·itemType· of IDREFS isIDREF.

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

3.3.13 integer

[Definition:] integer is·derived· from decimal by fixing the value of ·fractionDigits· to be 0and disallowing the trailing decimal point. 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· ofinteger is decimal.

3.3.14 nonPositiveInteger

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

3.3.15 negativeInteger

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

3.3.20 nonNegativeInteger

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

3.3.25 positiveInteger

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

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 is allowed to have is specified. Any property not identified as optional is required to be present; optional properties which are not present haveabsent as their value. Any property identified as a having a set, subset or ·list·value may have an empty value unless this is explicitly ruled out: this is not the same as absent. Any property value identified as a superset or a subset of some set may be equal to that set, unless a proper superset or subset is explicitly called for.

For more information on the notion of datatype (schema) components, see Schema Component Detailsof [XML Schema Part 1: Structures].

4.1 Simple Type Definition

Simple Type definitions provide for:

• Establishing the ·value space· and ·lexical space·of a datatype, through the combined set of ·constraining facet·s specified in the definition;
• Attaching a unique name (actually a QName) to the·value space· and ·lexical space·.

4.1.1 The Simple Type Definition Schema Component

The Simple Type Definition schema component has the following properties:

Datatypes are identified by their {name}and {target namespace}. Except for anonymous datatypes (those with no {name}), datatype definitions ·must· be uniquely identified within a 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} (which is a subset of the·value space· of {primitive type definition}). If {variety} is ·list·then the ·value space· of the datatype defined will be the set of finite-length sequence of values from the·value space· of {item type definition}. If {variety} is ·union· then the·value space· of the datatype defined will be the union of the ·value space·s of each datatype in{member type definitions}.

If {variety} is ·atomic·then the {variety} of {base type definition}must be ·atomic·. If {variety} is ·list·then the {variety} of {item type definition}must be either ·atomic· or ·union·. If {variety} is ·union·then{member type definitions} must be a list of datatype definitions.

The value of {facets} consists of the set of·facet·s 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 facet·s and their values.

If {final} is the empty set then the type can be used in deriving other types; the explicit values restriction,list and union prevent further derivations by ·restriction·, ·list· and·union· respectively.

4.1.2 XML Representation of Simple Type Definition Schema Components

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

<simpleType
final = (#all | List of (list | union | restriction))
id = ID
**name** = NCName
_{any attributes with non-schema namespace . . .}_>
Content: (annotation?, (restriction | list | union))

A ·derived· datatype can be ·derived·from a ·primitive· datatype or another·derived· datatype by one of three means: by restriction, by list or by union.

4.1.2.1 Derivation by restriction

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.

In this case, Sku is the name of the new·user-derived· datatype, string is its ·base type· and ·pattern·is the facet.

4.1.2.2 Derivation by list

<list
id = ID
itemType = QName
_{any attributes with non-schema namespace . . .}_>
Content: (annotation?, simpleType?)

A ·list· datatype must be ·derived·from an ·atomic· or a ·union· datatype, known as the·itemType· of the ·list· datatype. This yields a datatype whose ·value space· is composed of finite-length sequences of values from the ·value space· of the·itemType· and whose ·lexical space· is composed of space-separated lists of literals of the·itemType·.

A system might want to store lists of floating point values.

In this case, listOfFloat is the name of the new·user-derived· datatype, float is its·itemType· 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 facet·s can be used:

• ·length·
• ·maxLength·
• ·minLength·
• ·enumeration·
• ·pattern·
• ·whiteSpace·

regardless of the ·constraining facet·s that are applicable to the ·atomic· datatype that serves as the·itemType· of the ·list·.

For each of ·length·, ·maxLength·and ·minLength·, the_unit of length_ is measured in number of list items. The value of ·whiteSpace·is fixed to the value collapse.

4.1.2.3 Derivation by union

<union
id = ID
memberTypes = List of QName
_{any attributes with non-schema namespace . . .}_>
Content: (annotation?, simpleType*)

A ·union· datatype can be ·derived·from one or more ·atomic·, ·list· or other ·union· datatypes, known as the ·memberTypes·of that ·union· datatype.

As an example, taken from a typical display oriented text markup language, one might want to express font sizes as an integer between 8 and 72, or with one of the tokens "small", "medium" or "large". The ·union·type definition below would accomplish that.

<xsd:attribute name="size"> xsd:simpleType xsd:union xsd:simpleType <xsd:restriction base="xsd:positiveInteger"> <xsd:minInclusive value="8"/> <xsd:maxInclusive value="72"/> xsd:simpleType <xsd:restriction base="xsd:NMTOKEN"> <xsd:enumeration value="small"/> <xsd:enumeration value="medium"/> <xsd:enumeration value="large"/>

A header

this is a test

As mentioned in Union datatypes (§2.5.1.3), when a datatype is ·derived· from a·union· datatype, the only following·constraining facet·s can be used:

• ·pattern·
• ·enumeration·

regardless of the ·constraining facet·s that are applicable to the datatypes that participate in the ·union·

4.1.5 Constraints on Simple Type Definition Schema Components

Schema Component Constraint: applicable facets

The ·constraining facet·s which are allowed to be members of {facets} are dependent on{base type definition} as specified in the following table:

4.2 Fundamental Facets

4.2.1 equal
4.2.2 ordered
4.2.3 bounded
4.2.4 cardinality
4.2.5 numeric

4.2.1 equal

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

• for any a and b in the ·value space·, either a is equal to b, denoted a = b, or _a_is not equal to b, denoted a != b
• there is no pair a and b_from the ·value space· such that both_a = b and a != b
• for all a in the ·value space·,a = a
• for any a and _b_in the ·value space·,a = b if and only if b = a
• for any a, b and_c_ in the ·value space·, if a = b and_b = c_, then a = c
• for any a and _b_in the ·value space·if a = b, then _a_and b cannot be distinguished (i.e., equality is identity)
• the ·value space·s of all·primitive· datatypes are disjoint (they do not share any values)

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.

Note that in consequence of the above:

• given ·value space· A and·value space· B where_A_ and B are disjoint, every pair of values a from _A_and b from B,a != b
• two values which are members of the ·value space·of the same ·primitive· datatype may always be compared with each other
• if a datatype T is·derived· by ·union· from·memberTypes· A, B, ...then the ·value space· of T is the union of ·value space·s of its·memberTypes· A, B, .... Some values in the ·value space· of_T are also values in the·value space· of A. Other values in the ·value space· of_T will be values in the·value space· of B and so on. Values in the ·value space· of T_which are also in the ·value space· of_A can be compared with other values in the·value space· of A according to the above rules. Similarly for values of type_T_ and B and all the other·memberTypes·.
• if a datatype T' is ·derived·by ·restriction· from an atomic datatype T_then the ·value space· of T' is a subset of the ·value space· of T. Values in the ·value space·s of_T and T' can be compared according to the above rules
• if datatypes T' and T'' are·derived· by ·restriction· from a common atomic ancestor T then the·value space·s of T' and_T''_ may overlap. Values in the·value space·s of T' and T'' can be compared according to the above rules

Note: There is no schema component corresponding to the equal ·fundamental facet·.

4.2.2 ordered

[Definition:] Anorder relation on a ·value space·is a mathematical relation that imposes a·total order· or a ·partial order· on the members of the ·value space·.

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

[Definition:] A partial order is an ·order-relation·that is irreflexive, asymmetric andtransitive.

A ·partial order· has the following properties:

• for no a in the ·value space·,a < a(irreflexivity)
• for all a and _b_in the ·value space·,_a < b_implies not(b < a) (asymmetry)
• for all a, _b_and c in the ·value space·,a < b and _b < c_implies a < c(transitivity)

The notation a <> b is used to indicate the case when a != b and neither_a < b_ nor b < a_. For any values _a_ and _b_from different ·primitive· ·value space·s,_a <> b.

[Definition:] When a <> b, a and b are incomparable,[Definition:] otherwise they are comparable.

[Definition:] A total order is an ·partial order·such that for no a and _b_is it the case that a <> b.

A ·total order· has all of the properties specified above for ·partial order·, plus the following property:

• for all a and b in the ·value space·, either a < b or _b < a_or a = b

Note: The fact that this specification does not define an·order-relation· for some datatype does not mean that some other application cannot treat that datatype as being ordered by imposing its own order relation.

·ordered· provides for:

• indicating whether an ·order-relation· is defined on a ·value space·, and if so, whether that ·order-relation· is a ·partial order· or a ·total order·

4.2.2.1 The ordered Schema Component

{value}

One of {false, partial, total}.

{value} depends on {variety},{facets} and {member type definitions}in the Simple Type Definition component in which a·ordered· component appears as a member of{fundamental facets}.

When {variety} is ·atomic·,{value} is inherited from{value} of {base type definition}. For all ·primitive· types {value}is as specified in the table in Fundamental Facets (§C.1).

When {variety} is ·list·,{value} is false.

When {variety} is ·union·,{value} is partial unless one of the following:

• If every member of {member type definitions} is derived from a common ancestor other than the simple ur-type, then {value}is the same as that ancestor's ordered facet
• If every member of {member type definitions} has a{value} of false for the orderedfacet, then {value} is false

4.2.3 bounded

[Definition:] A value u in an ·ordered· ·value space· _U_is said to be an inclusive upper bound of a·value space· V(where V is a subset of U) if for all v in V,u >= v.

[Definition:] A value u in an ·ordered· ·value space· _U_is said to be an exclusive upper bound of a·value space· V(where V is a subset of U) if for all v in V,u > v.

[Definition:] A value l in an ·ordered· ·value space· _L_is said to be an inclusive lower bound of a·value space· V(where V is a subset of L) if for all v in V,l <= v.

[Definition:] A value l in an ·ordered· ·value space· _L_is said to be an exclusive lower bound of a·value space· V(where V is a subset of L) if for all v in V,l < v.

[Definition:] A datatype is boundedif its ·value space· has either an·inclusive upper bound· or an ·exclusive upper bound·and either an ·inclusive lower bound· or an·exclusive lower bound·.

·bounded· provides for:

• indicating whether a ·value space· is·bounded·

4.2.3.1 The bounded Schema Component

{value} depends on {variety},{facets} and {member type definitions}in the Simple Type Definition component in which a·bounded· component appears as a member of{fundamental facets}.

When {variety} is ·atomic·, if one of ·minInclusive· or ·minExclusive·and one of ·maxInclusive· or ·maxExclusive·are among {facets} , then{value} is true; else{value} is false.

When {variety} is ·list·, if ·length· or both of·minLength· and ·maxLength·are among {facets}, then{value} is true; else{value} is false.

When {variety} is ·union·, if {value} is _true_for every member of {member type definitions}and all members of {member type definitions} share a common ancestor, then {value} is true; else {value} is false.

4.2.4 cardinality

[Definition:] Every·value space· has associated with it the concept ofcardinality. Some ·value space·s are finite, some are countably infinite while still others could conceivably be uncountably infinite (although no ·value space·defined by this specification is uncountable infinite). A datatype is said to have the cardinality of its·value space·.

It is sometimes useful to categorize ·value space·s (and hence, datatypes) as to their cardinality. There are two significant cases:

• ·value space·s that are finite
• ·value space·s that are countably infinite

·cardinality· provides for:

• indicating whether the ·cardinality·of a ·value space· is_finite_ or countably infinite

4.2.4.1 The cardinality Schema Component

{value}

One of {finite, countably infinite}.

{value} depends on {variety},{facets} and {member type definitions}in the Simple Type Definition component in which a·cardinality· component appears as a member of{fundamental facets}.

When {variety} is ·atomic· and{value} of {base type definition}is finite, then {value} is_finite_.

When {variety} is ·atomic· and{value} of {base type definition}is countably infinite and either of the following conditions are true, then {value} is_finite_; else {value}is countably infinite:

1. one of ·length·, ·maxLength·,·totalDigits· is among {facets},
2. all of the following are true:
   1. one of ·minInclusive· or·minExclusive·is among {facets}
   2. one of ·maxInclusive· or·maxExclusive·is among {facets}
   3. either of the following are true:
      1. ·fractionDigits· is among {facets}
      2. {base type definition} is one of date,gYearMonth, gYear, gMonthDay,gDay or gMonth or any type ·derived·from them

When {variety} is ·list·, if ·length· or both of·minLength· and ·maxLength·are among {facets}, then{value} is finite; else{value} is countably infinite.

When {variety} is ·union·, if {value} is _finite_for every member of {member type definitions}, then{value} is finite; else {value} is countably infinite.

4.2.5 numeric

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

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

·numeric· provides for:

• indicating whether a ·value space· is·numeric·

4.3 Constraining Facets

4.3.1 length
4.3.2 minLength
4.3.3 maxLength
4.3.4 pattern
4.3.5 enumeration
4.3.6 whiteSpace
4.3.7 maxInclusive
4.3.8 maxExclusive
4.3.9 minExclusive
4.3.10 minInclusive
4.3.11 totalDigits
4.3.12 fractionDigits

4.3.1 length

[Definition:] length is the number of units of length, where _units of length_varies depending on the type that is being ·derived· from. The value oflength ·must· be anonNegativeInteger.

For string and datatypes ·derived· from string,length is measured in units of characters as defined in [XML 1.0 (Second Edition)]. For anyURI, length is measured in units of characters (as for string). For hexBinary and base64Binary and datatypes ·derived· from them,length is measured in octets (8 bits) of binary data. For datatypes ·derived· by ·list·,length is measured in number of list items.

Note: For string and datatypes ·derived· from string,length will not always coincide with "string length" as perceived by some users or with the number of storage units in some digital representation. Therefore, care should be taken when specifying a value for lengthand in attempting to infer storage requirements from a given value forlength.

·length· provides for:

• Constraining a ·value space·to values with a specific number of units of length, where _units of length_varies depending on {base type definition}.

The following is the definition of a ·user-derived·datatype to represent product codes which must be exactly 8 characters in length. By fixing the value of thelength facet we ensure that types derived from productCode can change or set the values of other facets, such as pattern, but cannot change the length.

4.3.1.3 length Validation Rules

Validation Rule: Length Valid

A value in a ·value space· is facet-valid with respect to ·length·, determined as follows:

1 if the {variety} is ·atomic· then

1.1 if {primitive type definition} is string or anyURI, then the length of the value, as measured in characters·must· be equal to {value};

1.2 if {primitive type definition} is hexBinary or base64Binary, then the length of the value, as measured in octets of the binary data,·must· be equal to {value};

1.3 if {primitive type definition} is QName or NOTATION, then any {value} is facet-valid.

2 if the {variety} is ·list·, then the length of the value, as measured in list items, ·must· be equal to {value}

The use of ·length·on datatypes ·derived· from QName and NOTATIONis deprecated. Future versions of this specification may remove this facet for these datatypes.

4.3.2 minLength

[Definition:] minLength is the minimum number of units of length, where_units of length_ varies depending on the type that is being·derived· from. The value of minLength ·must· be a nonNegativeInteger.

For string and datatypes ·derived· from string,minLength is measured in units of characters as defined in [XML 1.0 (Second Edition)]. For hexBinary and base64Binary and datatypes ·derived· from them,minLength is measured in octets (8 bits) of binary data. For datatypes ·derived· by ·list·,minLength is measured in number of list items.

Note: For string and datatypes ·derived· from string,minLength will not always coincide with "string length" as perceived by some users or with the number of storage units in some digital representation. Therefore, care should be taken when specifying a value for minLengthand in attempting to infer storage requirements from a given value forminLength.

·minLength· provides for:

• Constraining a ·value space·to values with at least a specific number of units of length, where _units of length_varies depending on {base type definition}.

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).

4.3.2.3 minLength Validation Rules

Validation Rule: minLength Valid

A value in a ·value space· is facet-valid with respect to ·minLength·, determined as follows:

1 if the {variety} is ·atomic· then

1.1 if {primitive type definition} is string oranyURI, then the length of the value, as measured incharacters·must· be greater than or equal to{value};

1.2 if {primitive type definition} is hexBinary or base64Binary, then the length of the value, as measured in octets of the binary data,·must· be greater than or equal to{value};

1.3 if {primitive type definition} is QName or NOTATION, then any {value} is facet-valid.

2 if the {variety} is ·list·, then the length of the value, as measured in list items, ·must· be greater than or equal to {value}

The use of ·minLength·on datatypes ·derived· from QName and NOTATIONis deprecated. Future versions of this specification may remove this facet for these datatypes.

4.3.3 maxLength

[Definition:] maxLength is the maximum number of units of length, where_units of length_ varies depending on the type that is being ·derived· from. The value of maxLength ·must· be a nonNegativeInteger.

For string and datatypes ·derived· from string,maxLength is measured in units of characters as defined in [XML 1.0 (Second Edition)]. For hexBinary and base64Binary and datatypes ·derived· from them,maxLength is measured in octets (8 bits) of binary data. For datatypes ·derived· by ·list·,maxLength is measured in number of list items.

Note: For string and datatypes ·derived· from string,maxLength will not always coincide with "string length" as perceived by some users or with the number of storage units in some digital representation. Therefore, care should be taken when specifying a value for maxLengthand in attempting to infer storage requirements from a given value formaxLength.

·maxLength· provides for:

• Constraining a ·value space·to values with at most a specific number of units of length, where _units of length_varies depending on {base type definition}.

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.

4.3.3.3 maxLength Validation Rules

Validation Rule: maxLength Valid

A value in a ·value space· is facet-valid with respect to ·maxLength·, determined as follows:

1 if the {variety} is ·atomic· then

1.1 if {primitive type definition} is string oranyURI, then the length of the value, as measured in characters·must· be less than or equal to{value};

1.2 if {primitive type definition} is hexBinary or base64Binary, then the length of the value, as measured in octets of the binary data,·must· be less than or equal to {value};

1.3 if {primitive type definition} is QName or NOTATION, then any {value} is facet-valid.

2 if the {variety} is ·list·, then the length of the value, as measured in list items, ·must· be less than or equal to{value}

The use of ·maxLength·on datatypes ·derived· from QName and NOTATIONis deprecated. Future versions of this specification may remove this facet for these datatypes.

4.3.4 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·.

·pattern· provides for:

• Constraining a ·value space·to values that are denoted by literals which match a specific·regular expression·.

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·.

4.3.4.3 Constraints on XML Representation of pattern

Note: It is a consequence of the schema representation constraintMultiple patterns (§4.3.4.3) and of the rules for·restriction· that ·pattern·facets specified on the same step in a type derivation are ORed together, while ·pattern·facets specified on different steps of a type derivation are ANDed together.

Thus, to impose two ·pattern· constraints simultaneously, schema authors may either write a single ·pattern· which expresses the intersection of the two ·pattern·s they wish to impose, or define each ·pattern· on a separate type derivation step.

4.3.5 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 value of the·ordered· property of the ·derived·datatype remains that of the datatype from which it is·derived·.

·enumeration· provides for:

• Constraining a ·value space·to a specified set of values.

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·.

4.3.6 whiteSpace

[Definition:] whiteSpace constrains the ·value space·of types ·derived· from string such that the various behaviors specified in Attribute Value Normalizationin [XML 1.0 (Second Edition)] are realized. The value ofwhiteSpace must be one of {preserve, replace, collapse}.

preserve

No normalization is done, the value is not changed (this is the behavior required by [XML 1.0 (Second Edition)] for element content)

replace

All occurrences of #x9 (tab), #xA (line feed) and #xD (carriage return) are replaced with #x20 (space)

collapse

After the processing implied by replace, contiguous sequences of #x20's are collapsed to a single #x20, and leading and trailing #x20's are removed.

Note: The notation #xA used here (and elsewhere in this specification) represents the Universal Character Set (UCS) code point hexadecimal A (line feed), which is denoted by U+000A. This notation is to be distinguished from 
, which is the XML character referenceto that same UCS code point.

whiteSpace is applicable to all ·atomic· and·list· datatypes. For all ·atomic·datatypes other than string (and types ·derived·by ·restriction· from it) the value of whiteSpace iscollapse and cannot be changed by a schema author; forstring the value of whiteSpace ispreserve; for any type ·derived· by·restriction· fromstring the value of whiteSpace can be any of the three legal values. For all datatypes·derived· by ·list· the value of whiteSpace is collapse and cannot be changed by a schema author. For all datatypes·derived· by ·union· whiteSpace does not apply directly; however, the normalization behavior of ·union· types is controlled by the value of whiteSpace on that one of the·memberTypes· against which the ·union·is successfully validated.

Note: For more information on whiteSpace, see the discussion on white space normalization inSchema Component Detailsin [XML Schema Part 1: Structures].

·whiteSpace· provides for:

• Constraining a ·value space· according to the white space normalization rules.

The following example is the datatype definition for the token ·built-in· ·derived·datatype.

4.3.7 maxInclusive

[Definition:] maxInclusive is the ·inclusive upper bound·of the ·value space· for a datatype with the·ordered· property. The value ofmaxInclusive ·must· be in the ·value space· of the·base type·.

·maxInclusive· provides for:

• Constraining a ·value space· to values with a specific ·inclusive upper bound·.

The following is the definition of a ·user-derived·datatype which limits values to integers less than or equal to 100, using ·maxInclusive·.

4.3.8 maxExclusive

[Definition:] maxExclusive is the ·exclusive upper bound·of the ·value space· for a datatype with the·ordered· property. The value of maxExclusive ·must· be in the ·value space· of the·base type· or be equal to {value} in{base type definition}.

·maxExclusive· provides for:

• Constraining a ·value space· to values with a specific ·exclusive upper bound·.

The following is the definition of a ·user-derived·datatype which limits values to integers less than or equal to 100, using ·maxExclusive·.

Note that the·value space· of this datatype is identical to the previous one (named 'one-hundred-or-less').

4.3.9 minExclusive

[Definition:] minExclusive is the ·exclusive lower bound·of the ·value space· for a datatype with the·ordered· property. The value of minExclusive ·must·be in the ·value space· of the·base type· or be equal to {value} in{base type definition}.

·minExclusive· provides for:

• Constraining a ·value space· to values with a specific ·exclusive lower bound·.

The following is the definition of a ·user-derived·datatype which limits values to integers greater than or equal to 100, using ·minExclusive·.

Note that the·value space· of this datatype is identical to the previous one (named 'one-hundred-or-more').

4.3.10 minInclusive

[Definition:] minInclusive is the ·inclusive lower bound·of the ·value space· for a datatype with the·ordered· property. The value ofminInclusive ·must· be in the ·value space· of the·base type·.

·minInclusive· provides for:

• Constraining a ·value space· to values with a specific ·inclusive lower bound·.

The following is the definition of a ·user-derived·datatype which limits values to integers greater than or equal to 100, using ·minInclusive·.

4.3.11 totalDigits

[Definition:] totalDigitscontrols the maximum number of values in the ·value space·of datatypes ·derived· from decimal, by restricting it to numbers that are expressible as_i × 10^-n_ where i_and n are integers such that|i| < 10^totalDigits_ and_0 <= n <= totalDigits_. The value oftotalDigits ·must· be apositiveInteger.

The term totalDigits is chosen to reflect the fact that it restricts the ·value space· to those values that can be represented lexically using at most _totalDigits_digits. Note that it does not restrict the ·lexical space·directly; a lexical representation that adds additional leading zero digits or trailing fractional zero digits is still permitted.

4.3.12 fractionDigits

[Definition:] fractionDigitscontrols the size of the minimum difference between values in the ·value space· of datatypes ·derived·from decimal, by restricting the ·value space· to numbers that are expressible as i × 10^-n where_i_ and _n_are integers and 0 <= n <= fractionDigits. The value of fractionDigits ·must·be a nonNegativeInteger.

The term fractionDigits is chosen to reflect the fact that it restricts the ·value space· to those values that can be represented lexically using at most _fractionDigits_to the right of the decimal point. Note that it does not restrict the·lexical space· directly; a non-·canonical lexical representation· that adds additional leading zero digits or trailing fractional zero digits is still permitted.

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 Celsius 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·.

A Schema for Datatype Definitions (normative)

    <!ENTITY % schemaAttrs 'xmlns:hfp CDATA #IMPLIED'>

    <!ELEMENT hfp:hasFacet EMPTY>
    <!ATTLIST hfp:hasFacet
            name NMTOKEN #REQUIRED>

    <!ELEMENT hfp:hasProperty EMPTY>
    <!ATTLIST hfp:hasProperty
            name NMTOKEN #REQUIRED
            value CDATA #REQUIRED>

    <!ATTLIST xs:simpleType id ID #IMPLIED>
    <!ATTLIST xs:maxExclusive id ID #IMPLIED>
    <!ATTLIST xs:minExclusive id ID #IMPLIED>
    <!ATTLIST xs:maxInclusive id ID #IMPLIED>
    <!ATTLIST xs:minInclusive id ID #IMPLIED>
    <!ATTLIST xs:totalDigits id ID #IMPLIED>
    <!ATTLIST xs:fractionDigits id ID #IMPLIED>
    <!ATTLIST xs:length id ID #IMPLIED>
    <!ATTLIST xs:minLength id ID #IMPLIED>
    <!ATTLIST xs:maxLength id ID #IMPLIED>
    <!ATTLIST xs:enumeration id ID #IMPLIED>
    <!ATTLIST xs:pattern id ID #IMPLIED>
    <!ATTLIST xs:appinfo id ID #IMPLIED>
    <!ATTLIST xs:documentation id ID #IMPLIED>
    <!ATTLIST xs:list id ID #IMPLIED>
    <!ATTLIST xs:union id ID #IMPLIED>
    ]>

<xs:schema xmlns:hfp="http://www.w3.org/2001/XMLSchema-hasFacetAndProperty" xmlns:xs="http://www.w3.org/2001/XMLSchema" blockDefault="#all" elementFormDefault="qualified" xml:lang="en" targetNamespace="http://www.w3.org/2001/XMLSchema" version="Id: datatypes.xsd,v 1.4 2004/05/29 10:26:33 ht Exp "> xs:annotation <xs:documentation source="../datatypes/datatypes-with-errata.html"> The schema corresponding to this document is normative, with respect to the syntactic constraints it expresses in the XML Schema language. The documentation (within <documentation> elements) below, is not normative, but rather highlights important aspects of the W3C Recommendation of which this is a part xs:annotation xs:documentation First the built-in primitive datatypes. These definitions are for information only, the real built-in definitions are magic. xs:documentation For each built-in datatype in this schema (both primitive and derived) can be uniquely addressed via a URI constructed as follows: 1) the base URI is the URI of the XML Schema namespace 2) the fragment identifier is the name of the datatype

  For example, to address the int datatype, the URI is:

    http://www.w3.org/2001/XMLSchema#int

  Additionally, each facet definition element can be uniquely
  addressed via a URI constructed as follows:
    1) the base URI is the URI of the XML Schema namespace
    2) the fragment identifier is the name of the facet

  For example, to address the maxInclusive facet, the URI is:

    http://www.w3.org/2001/XMLSchema#maxInclusive

  Additionally, each facet usage in a built-in datatype definition
  can be uniquely addressed via a URI constructed as follows:
    1) the base URI is the URI of the XML Schema namespace
    2) the fragment identifier is the name of the datatype, followed
       by a period (".") followed by the name of the facet

  For example, to address the usage of the maxInclusive facet in
  the definition of int, the URI is:

    http://www.w3.org/2001/XMLSchema#int.maxInclusive

</xs:documentation>

<xs:simpleType name="string" id="string"> xs:annotation xs:appinfo <hfp:hasFacet name="length"/> <hfp:hasFacet name="minLength"/> <hfp:hasFacet name="maxLength"/> <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#string"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace value="preserve" id="string.preserve"/> <xs:simpleType name="boolean" id="boolean"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="finite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#boolean"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="boolean.whiteSpace"/> <xs:simpleType name="float" id="float"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="true"/> <hfp:hasProperty name="cardinality" value="finite"/> <hfp:hasProperty name="numeric" value="true"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#float"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="float.whiteSpace"/> <xs:simpleType name="double" id="double"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="true"/> <hfp:hasProperty name="cardinality" value="finite"/> <hfp:hasProperty name="numeric" value="true"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#double"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="double.whiteSpace"/> <xs:simpleType name="decimal" id="decimal"> xs:annotation xs:appinfo <hfp:hasFacet name="totalDigits"/> <hfp:hasFacet name="fractionDigits"/> <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="total"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="true"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#decimal"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="decimal.whiteSpace"/> <xs:simpleType name="duration" id="duration"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#duration"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="duration.whiteSpace"/> <xs:simpleType name="dateTime" id="dateTime"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#dateTime"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="dateTime.whiteSpace"/> <xs:simpleType name="time" id="time"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#time"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="time.whiteSpace"/> <xs:simpleType name="date" id="date"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#date"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="date.whiteSpace"/> <xs:simpleType name="gYearMonth" id="gYearMonth"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#gYearMonth"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="gYearMonth.whiteSpace"/> <xs:simpleType name="gYear" id="gYear"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#gYear"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="gYear.whiteSpace"/> <xs:simpleType name="gMonthDay" id="gMonthDay"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#gMonthDay"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="gMonthDay.whiteSpace"/> <xs:simpleType name="gDay" id="gDay"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#gDay"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="gDay.whiteSpace"/> <xs:simpleType name="gMonth" id="gMonth"> xs:annotation xs:appinfo <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="maxInclusive"/> <hfp:hasFacet name="maxExclusive"/> <hfp:hasFacet name="minInclusive"/> <hfp:hasFacet name="minExclusive"/> <hfp:hasProperty name="ordered" value="partial"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#gMonth"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="gMonth.whiteSpace"/> <xs:simpleType name="hexBinary" id="hexBinary"> xs:annotation xs:appinfo <hfp:hasFacet name="length"/> <hfp:hasFacet name="minLength"/> <hfp:hasFacet name="maxLength"/> <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#binary"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="hexBinary.whiteSpace"/> <xs:simpleType name="base64Binary" id="base64Binary"> xs:annotation xs:appinfo <hfp:hasFacet name="length"/> <hfp:hasFacet name="minLength"/> <hfp:hasFacet name="maxLength"/> <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#base64Binary"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="base64Binary.whiteSpace"/> <xs:simpleType name="anyURI" id="anyURI"> xs:annotation xs:appinfo <hfp:hasFacet name="length"/> <hfp:hasFacet name="minLength"/> <hfp:hasFacet name="maxLength"/> <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#anyURI"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="anyURI.whiteSpace"/> <xs:simpleType name="QName" id="QName"> xs:annotation xs:appinfo <hfp:hasFacet name="length"/> <hfp:hasFacet name="minLength"/> <hfp:hasFacet name="maxLength"/> <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#QName"/> <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="QName.whiteSpace"/> <xs:simpleType name="NOTATION" id="NOTATION"> xs:annotation xs:appinfo <hfp:hasFacet name="length"/> <hfp:hasFacet name="minLength"/> <hfp:hasFacet name="maxLength"/> <hfp:hasFacet name="pattern"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#NOTATION"/> xs:documentation NOTATION cannot be used directly in a schema; rather a type must be derived from it by specifying at least one enumeration facet whose value is the name of a NOTATION declared in the schema. <xs:restriction base="xs:anySimpleType"> <xs:whiteSpace fixed="true" value="collapse" id="NOTATION.whiteSpace"/> xs:annotation xs:documentation Now the derived primitive types <xs:simpleType name="normalizedString" id="normalizedString"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#normalizedString"/> <xs:restriction base="xs:string"> <xs:whiteSpace value="replace" id="normalizedString.whiteSpace"/> <xs:simpleType name="token" id="token"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#token"/> <xs:restriction base="xs:normalizedString"> <xs:whiteSpace value="collapse" id="token.whiteSpace"/> <xs:simpleType name="language" id="language"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#language"/> <xs:restriction base="xs:token"> <xs:pattern value="[a-zA-Z]{1,8}(-[a-zA-Z0-9]{1,8})*" id="language.pattern"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.ietf.org/rfc/rfc3066.txt"> pattern specifies the content of section 2.12 of XML 1.0e2 and RFC 3066 (Revised version of RFC 1766). <xs:simpleType name="IDREFS" id="IDREFS"> xs:annotation xs:appinfo <hfp:hasFacet name="length"/> <hfp:hasFacet name="minLength"/> <hfp:hasFacet name="maxLength"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="pattern"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#IDREFS"/> xs:restriction xs:simpleType <xs:list itemType="xs:IDREF"/> <xs:minLength value="1" id="IDREFS.minLength"/> <xs:simpleType name="ENTITIES" id="ENTITIES"> xs:annotation xs:appinfo <hfp:hasFacet name="length"/> <hfp:hasFacet name="minLength"/> <hfp:hasFacet name="maxLength"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="pattern"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#ENTITIES"/> xs:restriction xs:simpleType <xs:list itemType="xs:ENTITY"/> <xs:minLength value="1" id="ENTITIES.minLength"/> <xs:simpleType name="NMTOKEN" id="NMTOKEN"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#NMTOKEN"/> <xs:restriction base="xs:token"> <xs:pattern value="\c+" id="NMTOKEN.pattern"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/REC-xml#NT-Nmtoken"> pattern matches production 7 from the XML spec <xs:simpleType name="NMTOKENS" id="NMTOKENS"> xs:annotation xs:appinfo <hfp:hasFacet name="length"/> <hfp:hasFacet name="minLength"/> <hfp:hasFacet name="maxLength"/> <hfp:hasFacet name="enumeration"/> <hfp:hasFacet name="whiteSpace"/> <hfp:hasFacet name="pattern"/> <hfp:hasProperty name="ordered" value="false"/> <hfp:hasProperty name="bounded" value="false"/> <hfp:hasProperty name="cardinality" value="countably infinite"/> <hfp:hasProperty name="numeric" value="false"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#NMTOKENS"/> xs:restriction xs:simpleType <xs:list itemType="xs:NMTOKEN"/> <xs:minLength value="1" id="NMTOKENS.minLength"/> <xs:simpleType name="Name" id="Name"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#Name"/> <xs:restriction base="xs:token"> <xs:pattern value="\i\c*" id="Name.pattern"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/REC-xml#NT-Name"> pattern matches production 5 from the XML spec <xs:simpleType name="NCName" id="NCName"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#NCName"/> <xs:restriction base="xs:Name"> <xs:pattern value="[\i-[:]][\c-[:]]*" id="NCName.pattern"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/REC-xml-names/#NT-NCName"> pattern matches production 4 from the Namespaces in XML spec <xs:simpleType name="ID" id="ID"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#ID"/> <xs:restriction base="xs:NCName"/> <xs:simpleType name="IDREF" id="IDREF"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#IDREF"/> <xs:restriction base="xs:NCName"/> <xs:simpleType name="ENTITY" id="ENTITY"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#ENTITY"/> <xs:restriction base="xs:NCName"/> <xs:simpleType name="integer" id="integer"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#integer"/> <xs:restriction base="xs:decimal"> <xs:fractionDigits fixed="true" value="0" id="integer.fractionDigits"/> <xs:pattern value="[-+]?[0-9]+"/> <xs:simpleType name="nonPositiveInteger" id="nonPositiveInteger"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#nonPositiveInteger"/> <xs:restriction base="xs:integer"> <xs:maxInclusive value="0" id="nonPositiveInteger.maxInclusive"/> <xs:simpleType name="negativeInteger" id="negativeInteger"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#negativeInteger"/> <xs:restriction base="xs:nonPositiveInteger"> <xs:maxInclusive value="-1" id="negativeInteger.maxInclusive"/> <xs:simpleType name="long" id="long"> xs:annotation xs:appinfo <hfp:hasProperty name="bounded" value="true"/> <hfp:hasProperty name="cardinality" value="finite"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#long"/> <xs:restriction base="xs:integer"> <xs:minInclusive value="-9223372036854775808" id="long.minInclusive"/> <xs:maxInclusive value="9223372036854775807" id="long.maxInclusive"/> <xs:simpleType name="int" id="int"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#int"/> <xs:restriction base="xs:long"> <xs:minInclusive value="-2147483648" id="int.minInclusive"/> <xs:maxInclusive value="2147483647" id="int.maxInclusive"/> <xs:simpleType name="short" id="short"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#short"/> <xs:restriction base="xs:int"> <xs:minInclusive value="-32768" id="short.minInclusive"/> <xs:maxInclusive value="32767" id="short.maxInclusive"/> <xs:simpleType name="byte" id="byte"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#byte"/> <xs:restriction base="xs:short"> <xs:minInclusive value="-128" id="byte.minInclusive"/> <xs:maxInclusive value="127" id="byte.maxInclusive"/> <xs:simpleType name="nonNegativeInteger" id="nonNegativeInteger"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#nonNegativeInteger"/> <xs:restriction base="xs:integer"> <xs:minInclusive value="0" id="nonNegativeInteger.minInclusive"/> <xs:simpleType name="unsignedLong" id="unsignedLong"> xs:annotation xs:appinfo <hfp:hasProperty name="bounded" value="true"/> <hfp:hasProperty name="cardinality" value="finite"/> <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#unsignedLong"/> <xs:restriction base="xs:nonNegativeInteger"> <xs:maxInclusive value="18446744073709551615" id="unsignedLong.maxInclusive"/> <xs:simpleType name="unsignedInt" id="unsignedInt"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#unsignedInt"/> <xs:restriction base="xs:unsignedLong"> <xs:maxInclusive value="4294967295" id="unsignedInt.maxInclusive"/> <xs:simpleType name="unsignedShort" id="unsignedShort"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#unsignedShort"/> <xs:restriction base="xs:unsignedInt"> <xs:maxInclusive value="65535" id="unsignedShort.maxInclusive"/> <xs:simpleType name="unsignedByte" id="unsignedByte"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#unsignedByte"/> <xs:restriction base="xs:unsignedShort"> <xs:maxInclusive value="255" id="unsignedByte.maxInclusive"/> <xs:simpleType name="positiveInteger" id="positiveInteger"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#positiveInteger"/> <xs:restriction base="xs:nonNegativeInteger"> <xs:minInclusive value="1" id="positiveInteger.minInclusive"/> <xs:simpleType name="derivationControl"> xs:annotation xs:documentation A utility type, not for public use <xs:restriction base="xs:NMTOKEN"> <xs:enumeration value="substitution"/> <xs:enumeration value="extension"/> <xs:enumeration value="restriction"/> <xs:enumeration value="list"/> <xs:enumeration value="union"/> <xs:group name="simpleDerivation"> xs:choice <xs:element ref="xs:restriction"/> <xs:element ref="xs:list"/> <xs:element ref="xs:union"/> <xs:simpleType name="simpleDerivationSet"> xs:annotation xs:documentation #all or (possibly empty) subset of {restriction, union, list} xs:documentation A utility type, not for public use xs:union xs:simpleType <xs:restriction base="xs:token"> <xs:enumeration value="#all"/> xs:simpleType xs:list xs:simpleType <xs:restriction base="xs:derivationControl"> <xs:enumeration value="list"/> <xs:enumeration value="union"/> <xs:enumeration value="restriction"/> <xs:complexType name="simpleType" abstract="true"> xs:complexContent <xs:extension base="xs:annotated"> <xs:group ref="xs:simpleDerivation"/> <xs:attribute name="final" type="xs:simpleDerivationSet"/> <xs:attribute name="name" type="xs:NCName"> xs:annotation xs:documentation Can be restricted to required or forbidden <xs:complexType name="topLevelSimpleType"> xs:complexContent <xs:restriction base="xs:simpleType"> xs:sequence <xs:element ref="xs:annotation" minOccurs="0"/> <xs:group ref="xs:simpleDerivation"/> <xs:attribute name="name" type="xs:NCName" use="required"> xs:annotation xs:documentation Required at the top level <xs:anyAttribute namespace="##other" processContents="lax"/> <xs:complexType name="localSimpleType"> xs:complexContent <xs:restriction base="xs:simpleType"> xs:sequence <xs:element ref="xs:annotation" minOccurs="0"/> <xs:group ref="xs:simpleDerivation"/> <xs:attribute name="name" use="prohibited"> xs:annotation xs:documentation Forbidden when nested <xs:attribute name="final" use="prohibited"/> <xs:anyAttribute namespace="##other" processContents="lax"/> <xs:element name="simpleType" type="xs:topLevelSimpleType" id="simpleType"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-simpleType"/> <xs:group name="facets"> xs:annotation xs:documentation We should use a substitution group for facets, but that's ruled out because it would allow users to add their own, which we're not ready for yet. xs:choice <xs:element ref="xs:minExclusive"/> <xs:element ref="xs:minInclusive"/> <xs:element ref="xs:maxExclusive"/> <xs:element ref="xs:maxInclusive"/> <xs:element ref="xs:totalDigits"/> <xs:element ref="xs:fractionDigits"/> <xs:element ref="xs:length"/> <xs:element ref="xs:minLength"/> <xs:element ref="xs:maxLength"/> <xs:element ref="xs:enumeration"/> <xs:element ref="xs:whiteSpace"/> <xs:element ref="xs:pattern"/> <xs:group name="simpleRestrictionModel"> xs:sequence <xs:element name="simpleType" type="xs:localSimpleType" minOccurs="0"/> <xs:group ref="xs:facets" minOccurs="0" maxOccurs="unbounded"/> <xs:element name="restriction" id="restriction"> xs:complexType xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-restriction"> base attribute and simpleType child are mutually exclusive, but one or other is required xs:complexContent <xs:extension base="xs:annotated"> <xs:group ref="xs:simpleRestrictionModel"/> <xs:attribute name="base" type="xs:QName" use="optional"/> <xs:element name="list" id="list"> xs:complexType xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-list"> itemType attribute and simpleType child are mutually exclusive, but one or other is required xs:complexContent <xs:extension base="xs:annotated"> xs:sequence <xs:element name="simpleType" type="xs:localSimpleType" minOccurs="0"/> <xs:attribute name="itemType" type="xs:QName" use="optional"/> <xs:element name="union" id="union"> xs:complexType xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-union"> memberTypes attribute must be non-empty or there must be at least one simpleType child xs:complexContent <xs:extension base="xs:annotated"> xs:sequence <xs:element name="simpleType" type="xs:localSimpleType" minOccurs="0" maxOccurs="unbounded"/> <xs:attribute name="memberTypes" use="optional"> xs:simpleType <xs:list itemType="xs:QName"/> <xs:complexType name="facet"> xs:complexContent <xs:extension base="xs:annotated"> <xs:attribute name="value" use="required"/> <xs:attribute name="fixed" type="xs:boolean" default="false" use="optional"/> <xs:complexType name="noFixedFacet"> xs:complexContent <xs:restriction base="xs:facet"> xs:sequence <xs:element ref="xs:annotation" minOccurs="0"/> <xs:attribute name="fixed" use="prohibited"/> <xs:anyAttribute namespace="##other" processContents="lax"/> <xs:element name="minExclusive" type="xs:facet" id="minExclusive"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-minExclusive"/> <xs:element name="minInclusive" type="xs:facet" id="minInclusive"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-minInclusive"/> <xs:element name="maxExclusive" type="xs:facet" id="maxExclusive"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-maxExclusive"/> <xs:element name="maxInclusive" type="xs:facet" id="maxInclusive"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-maxInclusive"/> <xs:complexType name="numFacet"> xs:complexContent <xs:restriction base="xs:facet"> xs:sequence <xs:element ref="xs:annotation" minOccurs="0"/> <xs:attribute name="value" type="xs:nonNegativeInteger" use="required"/> <xs:anyAttribute namespace="##other" processContents="lax"/> <xs:element name="totalDigits" id="totalDigits"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-totalDigits"/> xs:complexType xs:complexContent <xs:restriction base="xs:numFacet"> xs:sequence <xs:element ref="xs:annotation" minOccurs="0"/> <xs:attribute name="value" type="xs:positiveInteger" use="required"/> <xs:anyAttribute namespace="##other" processContents="lax"/> <xs:element name="fractionDigits" type="xs:numFacet" id="fractionDigits"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-fractionDigits"/> <xs:element name="length" type="xs:numFacet" id="length"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-length"/> <xs:element name="minLength" type="xs:numFacet" id="minLength"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-minLength"/> <xs:element name="maxLength" type="xs:numFacet" id="maxLength"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-maxLength"/> <xs:element name="enumeration" type="xs:noFixedFacet" id="enumeration"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-enumeration"/> <xs:element name="whiteSpace" id="whiteSpace"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-whiteSpace"/> xs:complexType xs:complexContent <xs:restriction base="xs:facet"> xs:sequence <xs:element ref="xs:annotation" minOccurs="0"/> <xs:attribute name="value" use="required"> xs:simpleType <xs:restriction base="xs:NMTOKEN"> <xs:enumeration value="preserve"/> <xs:enumeration value="replace"/> <xs:enumeration value="collapse"/> <xs:anyAttribute namespace="##other" processContents="lax"/> <xs:element name="pattern" id="pattern"> xs:annotation <xs:documentation source="" title="undefined" rel="noopener noreferrer">http://www.w3.org/TR/xmlschema-2/#element-pattern"/> xs:complexType xs:complexContent <xs:restriction base="xs:noFixedFacet"> xs:sequence <xs:element ref="xs:annotation" minOccurs="0"/> <xs:attribute name="value" type="xs:string" use="required"/> <xs:anyAttribute namespace="##other" processContents="lax"/>

B DTD for Datatype Definitions (non-normative)

C Datatypes and Facets

C.1 Fundamental Facets

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

| | Datatype | ordered | bounded | cardinality | numeric | | | ----------------------------------------- | ------------------------------------- | ---------------------- | ------------------------------ | ---------------------- | ----- | | primitive | string | false | false | countably infinite | false | | boolean | false | false | finite | false | | | float | partial | true | finite | true | | | double | partial | true | finite | true | | | decimal | total | false | countably infinite | true | | | duration | partial | false | countably infinite | false | | | dateTime | partial | false | countably infinite | false | | | time | partial | false | countably infinite | false | | | date | partial | false | countably infinite | false | | | gYearMonth | partial | false | countably infinite | false | | | gYear | partial | false | countably infinite | false | | | gMonthDay | partial | false | countably infinite | false | | | gDay | partial | false | countably infinite | false | | | gMonth | partial | false | countably infinite | false | | | hexBinary | false | false | countably infinite | false | | | base64Binary | false | false | countably infinite | false | | | anyURI | false | false | countably infinite | false | | | QName | false | false | countably infinite | false | | | NOTATION | false | false | countably infinite | false | | | derived | normalizedString | false | false | countably infinite | false | | token | false | false | countably infinite | false | | | language | false | false | countably infinite | false | | | IDREFS | false | false | countably infinite | false | | | ENTITIES | false | false | countably infinite | false | | | NMTOKEN | false | false | countably infinite | false | | | NMTOKENS | false | false | countably infinite | false | | | Name | false | false | countably infinite | false | | | NCName | false | false | countably infinite | false | | | ID | false | false | countably infinite | false | | | IDREF | false | false | countably infinite | false | | | ENTITY | false | false | countably infinite | false | | | integer | total | false | countably infinite | true | | | nonPositiveInteger | total | false | countably infinite | true | | | negativeInteger | total | false | countably infinite | true | | | long | total | true | finite | true | | | int | total | true | finite | true | | | short | total | true | finite | true | | | byte | total | true | finite | true | | | nonNegativeInteger | total | false | countably infinite | true | | | unsignedLong | total | true | finite | true | | | unsignedInt | total | true | finite | true | | | unsignedShort | total | true | finite | true | | | unsignedByte | total | true | finite | true | | | positiveInteger | total | false | countably infinite | true | |

D ISO 8601 Date and Time Formats

D.1 ISO 8601 Conventions

The ·primitive· datatypesduration, dateTime, time,date, gYearMonth, gMonthDay,gDay, gMonth and gYearuse lexical formats inspired by[ISO 8601]. Following [ISO 8601], the lexical forms of these datatypes can include only the characters #20 through #7F. 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 proleptic Gregorian calendar and times and representations of periods of time". The proleptic Gregorian calendar includes dates prior to 1582 (the year it came into use as an ecclesiastical calendar). 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.

[ISO 8601] lexical formats are described using "pictures" in which characters are used in place of decimal digits. The allowed decimal digits are (#x30-#x39). For the primitive datatypesdateTime, time,date, gYearMonth, gMonthDay,gDay, gMonth and gYear. 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 24. If the value of the hour element is 24 then the values of the minutes element and the seconds element must be 00 and 00.
• m -- represents a digit used in the time element "minute". The two digits in a mm format can have values from 0 to 59.
• 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". A value of 60 or more is allowed only in the case of leap seconds.
  Strictly speaking, a value of 60 or more is not sensible unless the month and day could represent March 31, June 30, September 30, or December 31 in UTC. Because the leap second is added or subtracted as the last second of the day in UTC time, the long (or short) minute could occur at other times in local time. In cases where the leap second is used with an inappropriate month and day it, and any fractional seconds, should considered as added or subtracted from the following minute.

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 dateTime.
• 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) indateTime, time,date, gYearMonth, gMonthDay,gDay, gMonth, and gYear.

In the lexical format for duration the following characters are also used as designators and appear as themselves in lexical formats:

• P -- is used as the time duration designator, preceding a data element representing a given duration of time.
• Y -- follows the number of years in a time duration.
• M -- follows the number of months or minutes in a time duration.
• D -- follows the number of days in a time duration.
• H -- follows the number of hours in a time duration.
• S -- follows the number of seconds in a time duration.

The values of the Year, Month, Day, Hour and Minutes components are not restricted but allow an arbitrary integer. Similarly, the value of the Seconds component allows an arbitrary decimal. Thus, the lexical format forduration and datatypes derived from it does not follow the alternative format of § 5.5.3.2.1 of [ISO 8601].

D.2 Truncated and Reduced Formats

[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 dateTimewhich represents an instant of time that recurs every day. Similarly, the gMonthDay and gDaydatatypes use left-truncated formats for date. The datatype gMonth uses a right and left truncated format fordate.

[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 dateTime are used as lexical representations for date, gMonth,gYear.

E Adding durations to dateTimes

Given a dateTime S and a duration D, this appendix specifies how to compute a dateTime E where E is the end of the time period with start S and duration D i.e. E = S + D. Such computations are used, for example, to determine whether a dateTimeis within a specific time period. This appendix also addresses the addition ofdurations to the datatypes date,gYearMonth, gYear, gDay andgMonth, which can be viewed as a set of dateTimes. In such cases, the addition is made to the first or startingdateTime in the set.

This is a logical explanation of the process. Actual implementations are free to optimize as long as they produce the same results. The calculation uses the notation S[year] to represent the year field of S, S[month] to represent the month field, and so on. It also depends on the following functions:

• fQuotient(a, b) = the greatest integer less than or equal to a/b
  • fQuotient(-1,3) = -1
  • fQuotient(0,3)...fQuotient(2,3) = 0
  • fQuotient(3,3) = 1
  • fQuotient(3.123,3) = 1
• modulo(a, b) = a - fQuotient(a,b)*b
  • modulo(-1,3) = 2
  • modulo(0,3)...modulo(2,3) = 0...2
  • modulo(3,3) = 0
  • modulo(3.123,3) = 0.123
• fQuotient(a, low, high) = fQuotient(a - low, high - low)
  • fQuotient(0, 1, 13) = -1
  • fQuotient(1, 1, 13) ... fQuotient(12, 1, 13) = 0
  • fQuotient(13, 1, 13) = 1
  • fQuotient(13.123, 1, 13) = 1
• modulo(a, low, high) = modulo(a - low, high - low) + low
  • modulo(0, 1, 13) = 12
  • modulo(1, 1, 13) ... modulo(12, 1, 13) = 1...12
  • modulo(13, 1, 13) = 1
  • modulo(13.123, 1, 13) = 1.123
• maximumDayInMonthFor(yearValue, monthValue) =
  • M := modulo(monthValue, 1, 13)
  • Y := yearValue + fQuotient(monthValue, 1, 13)
  • Return a value based on M and Y:

E.1 Algorithm

Essentially, this calculation is equivalent to separating D into <year,month> and <day,hour,minute,second> fields. The <year,month> is added to S. If the day is out of range, it is pinned to be within range. Thus April 31 turns into April 30. Then the <day,hour,minute,second> is added. This latter addition can cause the year and month to change.

Leap seconds are handled by the computation by treating them as overflows. Essentially, a value of 60 seconds in S is treated as if it were a duration of 60 seconds added to S (with a zero seconds field). All calculations thereafter use 60 seconds per minute.

Thus the addition of either PT1M or PT60S to any dateTime will always produce the same result. This is a special definition of addition which is designed to match common practice, and -- most importantly -- be stable over time.

A definition that attempted to take leap-seconds into account would need to be constantly updated, and could not predict the results of future implementation's additions. The decision to introduce a leap second in UTC is the responsibility of the [International Earth Rotation Service (IERS)]. They make periodic announcements as to when leap seconds are to be added, but this is not known more than a year in advance. For more information on leap seconds, see [U.S. Naval Observatory Time Service Department].

The following is the precise specification. These steps must be followed in the same order. If a field in D is not specified, it is treated as if it were zero. If a field in S is not specified, it is treated in the calculation as if it were the minimum allowed value in that field, however, after the calculation is concluded, the corresponding field in E is removed (set to unspecified).

• Months (may be modified additionally below)
  • temp := S[month] + D[month]
  • E[month] := modulo(temp, 1, 13)
  • carry := fQuotient(temp, 1, 13)
• Years (may be modified additionally below)
  • E[year] := S[year] + D[year] + carry
• Zone
  • E[zone] := S[zone]
• Seconds
  • temp := S[second] + D[second]
  • E[second] := modulo(temp, 60)
  • carry := fQuotient(temp, 60)
• Minutes
  • temp := S[minute] + D[minute] + carry
  • E[minute] := modulo(temp, 60)
  • carry := fQuotient(temp, 60)
• Hours
  • temp := S[hour] + D[hour] + carry
  • E[hour] := modulo(temp, 24)
  • carry := fQuotient(temp, 24)
• Days
  • if S[day] > maximumDayInMonthFor(E[year], E[month])
    * tempDays := maximumDayInMonthFor(E[year], E[month])
  • else if S[day] < 1
    * tempDays := 1
  • else
    * tempDays := S[day]
  • E[day] := tempDays + D[day] + carry
  • START LOOP
    * IF E[day] < 1
    * E[day] := E[day] + maximumDayInMonthFor(E[year], E[month] - 1)
    * carry := -1
    * **ELSE IF** E[day] > maximumDayInMonthFor(E[year], E[month])
    * E[day] := E[day] - maximumDayInMonthFor(E[year], E[month])
    * carry := 1
    * ELSE EXIT LOOP
    * temp := E[month] + carry
    * E[month] := modulo(temp, 1, 13)
    * E[year] := E[year] + fQuotient(temp, 1, 13)
    * GOTO START LOOP

Examples:

F 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·, aregular expression R asserts that only strings in L(R) are valid literals for values of that type.

Note: Unlike some popular regular expression languages (including those defined by Perl and standard Unix utilities), the regular expression language defined here implicitly anchors all regular expressions at the head and tail, as the most common use of regular expressions in ·pattern· is to match entire literals. For example, a datatype ·derived· from string such that all values must begin with the character A (#x41) and end with the characterZ (#x5a) would be defined as follows:

In regular expression languages that are not implicitly anchored at the head and tail, it is customary to write the equivalent regular expression as:

^A.*Z$

where "^" anchors the pattern at the head and "$" anchors at the tail.

In those rare cases where an unanchored match is desired, including.* at the beginning and ending of the regular expression will achieve the desired results. For example, a datatype ·derived· from string such that all values must contain at least 3 consecutive A (#x41) characters somewhere within the value could be defined as follows:

[Definition:] Aregular expression is composed from zero or more·branch·es, separated by | characters.

[Definition:] A branch consists of zero or more ·piece·s, concatenated together.

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

Note: The regular expression language in the Perl Programming Language[Perl] does not include a quantifier of the formS{,m}, since it is logically equivalent to S{0,m}. We have, therefore, left this logical possibility out of the regular expression language defined by this specification.

[Definition:] A quantifieris 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·.

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

[Definition:] Anormal character is any XML character that is not a metacharacter. In ·regular expression·s, 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.

F.1 Character Classes

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

[Definition:] A positive character group consists of one or more·character range·s or ·character class escape·s, 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.

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

[Definition:] Acharacter 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:] Acharacter range R identifies a set of characters C(R) containing all XML characters with UCS 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 characters are valid character ranges, except as follows:

• The [, ], - and \ characters are not valid character ranges;
• The ^ character is only valid at the beginning of a·positive character group· if it is part of a·negative character group·
• The - character is a valid character range only at the beginning or end of a ·positive character group·.

Note: The grammar for ·character range· as given above is ambiguous, but the second and third bullets above together remove the ambiguity.

A ·character range· ·may· also be written in the form s-e, identifying the set that contains all XML characters with UCS 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:

• s is a ·single character escape·, or an XML character;
• s is not \
• If s is the first character in a ·character class expression·, then_s_ is not ^
• e is a ·single character escape·, or an XML character;
• e is not \ or [; and
• The code point of e is greater than or equal to the code point of s;

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.

F.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 are the ·single character escape·s, the·multi-character escape·s, and the ·category escape·s (including the ·block escape·s).

[Definition:] Asingle 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·.

[Definition:] [Unicode Database] specifies a number of possible values for the "General Category" property and provides mappings from code points to specific character properties. The set containing all characters that have property X, can be identified with a category escape \p{X}. The complement of this set is specified with thecategory escape \P{X}. ([\P{X}] = [^\p{X}]).

Note: [Unicode Database] is subject to future revision. For example, the mapping from code points to character properties might be updated. All ·minimally conforming· processors ·must·support the character properties defined in the version of [Unicode Database]that is current at the time this specification became a W3C Recommendation. However, implementors are encouraged to support the character properties defined in any future version.

The following table specifies the recognized values of the "General Category" property.

Note: The properties mentioned above exclude the Cs property. The Cs property identifies "surrogate" characters, which do not occur at the level of the "character abstraction" that XML instance documents operate on.

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

The following table specifies the recognized block names (for more information, see the "Blocks.txt" file in [Unicode Database]).

| Start Code | End Code | Block Name | | Start Code | End Code | Block Name | | ---------- | -------- | ---------------------------------- | | ---------- | -------- | -------------------------------- | | #x0000 | #x007F | BasicLatin | | #x0080 | #x00FF | Latin-1Supplement | | #x0100 | #x017F | LatinExtended-A | | #x0180 | #x024F | LatinExtended-B | | #x0250 | #x02AF | IPAExtensions | | #x02B0 | #x02FF | SpacingModifierLetters | | #x0300 | #x036F | CombiningDiacriticalMarks | | #x0370 | #x03FF | Greek | | #x0400 | #x04FF | Cyrillic | | #x0530 | #x058F | Armenian | | #x0590 | #x05FF | Hebrew | | #x0600 | #x06FF | Arabic | | #x0700 | #x074F | Syriac | | #x0780 | #x07BF | Thaana | | #x0900 | #x097F | Devanagari | | #x0980 | #x09FF | Bengali | | #x0A00 | #x0A7F | Gurmukhi | | #x0A80 | #x0AFF | Gujarati | | #x0B00 | #x0B7F | Oriya | | #x0B80 | #x0BFF | Tamil | | #x0C00 | #x0C7F | Telugu | | #x0C80 | #x0CFF | Kannada | | #x0D00 | #x0D7F | Malayalam | | #x0D80 | #x0DFF | Sinhala | | #x0E00 | #x0E7F | Thai | | #x0E80 | #x0EFF | Lao | | #x0F00 | #x0FFF | Tibetan | | #x1000 | #x109F | Myanmar | | #x10A0 | #x10FF | Georgian | | #x1100 | #x11FF | HangulJamo | | #x1200 | #x137F | Ethiopic | | #x13A0 | #x13FF | Cherokee | | #x1400 | #x167F | UnifiedCanadianAboriginalSyllabics | | #x1680 | #x169F | Ogham | | #x16A0 | #x16FF | Runic | | #x1780 | #x17FF | Khmer | | #x1800 | #x18AF | Mongolian | | #x1E00 | #x1EFF | LatinExtendedAdditional | | #x1F00 | #x1FFF | GreekExtended | | #x2000 | #x206F | GeneralPunctuation | | #x2070 | #x209F | SuperscriptsandSubscripts | | #x20A0 | #x20CF | CurrencySymbols | | #x20D0 | #x20FF | CombiningMarksforSymbols | | #x2100 | #x214F | LetterlikeSymbols | | #x2150 | #x218F | NumberForms | | #x2190 | #x21FF | Arrows | | #x2200 | #x22FF | MathematicalOperators | | #x2300 | #x23FF | MiscellaneousTechnical | | #x2400 | #x243F | ControlPictures | | #x2440 | #x245F | OpticalCharacterRecognition | | #x2460 | #x24FF | EnclosedAlphanumerics | | #x2500 | #x257F | BoxDrawing | | #x2580 | #x259F | BlockElements | | #x25A0 | #x25FF | GeometricShapes | | #x2600 | #x26FF | MiscellaneousSymbols | | #x2700 | #x27BF | Dingbats | | #x2800 | #x28FF | BraillePatterns | | #x2E80 | #x2EFF | CJKRadicalsSupplement | | #x2F00 | #x2FDF | KangxiRadicals | | #x2FF0 | #x2FFF | IdeographicDescriptionCharacters | | #x3000 | #x303F | CJKSymbolsandPunctuation | | #x3040 | #x309F | Hiragana | | #x30A0 | #x30FF | Katakana | | #x3100 | #x312F | Bopomofo | | #x3130 | #x318F | HangulCompatibilityJamo | | #x3190 | #x319F | Kanbun | | #x31A0 | #x31BF | BopomofoExtended | | #x3200 | #x32FF | EnclosedCJKLettersandMonths | | #x3300 | #x33FF | CJKCompatibility | | #x3400 | #x4DB5 | CJKUnifiedIdeographsExtensionA | | #x4E00 | #x9FFF | CJKUnifiedIdeographs | | #xA000 | #xA48F | YiSyllables | | #xA490 | #xA4CF | YiRadicals | | #xAC00 | #xD7A3 | HangulSyllables | | | | | | | | | | | #xE000 | #xF8FF | PrivateUse | | | | | | #xF900 | #xFAFF | CJKCompatibilityIdeographs | | #xFB00 | #xFB4F | AlphabeticPresentationForms | | #xFB50 | #xFDFF | ArabicPresentationForms-A | | #xFE20 | #xFE2F | CombiningHalfMarks | | #xFE30 | #xFE4F | CJKCompatibilityForms | | #xFE50 | #xFE6F | SmallFormVariants | | #xFE70 | #xFEFE | ArabicPresentationForms-B | | #xFEFF | #xFEFF | Specials | | #xFF00 | #xFFEF | HalfwidthandFullwidthForms | | #xFFF0 | #xFFFD | Specials |

Note: The blocks mentioned above exclude the HighSurrogates,LowSurrogates and HighPrivateUseSurrogates blocks. These blocks identify "surrogate" characters, which do not occur at the level of the "character abstraction" that XML instance documents operate on.

Note: [Unicode Database] is subject to future revision. For example, the grouping of code points into blocks might be updated. All ·minimally conforming· processors ·must·support the blocks defined in the version of [Unicode Database]that is current at the time this specification became a W3C Recommendation. However, implementors are encouraged to support the blocks defined in any future version of the Unicode Standard.

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

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

Note: The ·regular expression· language defined here does not attempt to provide a general solution to "regular expressions" over UCS character sequences. In particular, it does not easily provide for matching sequences of base characters and combining marks. The language is targeted at support of "Level 1" features as defined in[Unicode Regular Expression Guidelines]. It is hoped that future versions of this specification will provide support for "Level 2" features.

G Glossary (non-normative)

The listing below is for the benefit of readers of a printed version of this document: it collects together all the definitions which appear in the document above.

atomic

Atomic datatypes are those having values which are regarded by this specification as being indivisible.

base type

Every datatype that is ·derived· by restrictionis defined in terms of an existing datatype, referred to as itsbase type. base types can be either·primitive· or ·derived·.

bounded

A datatype is boundedif its ·value space· has either an·inclusive upper bound· or an ·exclusive upper bound·and either an ·inclusive lower bound· or an·exclusive lower bound·.

built-in

Built-indatatypes are those which are defined in this specification, and can be either ·primitive· or·derived·;

canonical lexical representation

A canonical lexical representationis a set of literals from among the valid set of literals for a datatype such that there is a one-to-one mapping between literals in the canonical lexical representation and values in the ·value space·.

cardinality

Every·value space· has associated with it the concept ofcardinality. Some ·value space·s are finite, some are countably infinite while still others could conceivably be uncountably infinite (although no ·value space·defined by this specification is uncountable infinite). A datatype is said to have the cardinality of its·value space·.

comparable

otherwise they are comparable.

conformance to the XML Representation of Schemas

Processors which accept schemas in the form of XML documents as described in XML Representation of Simple Type Definition Schema Components (§4.1.2) (and other relevant portions ofDatatype components (§4)) are additionally said to provideconformance to the XML Representation of Schemas, and ·must·, when processing schema documents, completely and correctly implement all·Schema Representation Constraint·s in this specification, and ·must· adhere exactly to the specifications in XML Representation of Simple Type Definition Schema Components (§4.1.2) (and other relevant portions ofDatatype components (§4)) for mapping the contents of such documents to schema componentsfor use in validation.

constraining facet

Aconstraining facet is an optional property that can be applied to a datatype to constrain its ·value space·.

Constraint on Schemas

Constraint on Schemas

datatype

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 ·facet·s that characterize properties of the ·value space·, individual values or lexical items.

derived

Deriveddatatypes are those that are defined in terms of other datatypes.

error

error

exclusive lower bound

A value l in an ·ordered· ·value space· _L_is said to be an exclusive lower bound of a·value space· V(where V is a subset of L) if for all v in V,l < v.

exclusive upper bound

A value u in an ·ordered· ·value space· _U_is said to be an exclusive upper bound of a·value space· V(where V is a subset of U) if for all v in V,u > v.

facet

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

for compatibility

for compatibility

fundamental facet

A fundamental facet is an abstract property which serves to semantically characterize the values in a·value space·.

inclusive lower bound

A value l in an ·ordered· ·value space· _L_is said to be an inclusive lower bound of a·value space· V(where V is a subset of L) if for all v in V,l <= v.

inclusive upper bound

A value u in an ·ordered· ·value space· _U_is said to be an inclusive upper bound of a·value space· V(where V is a subset of U) if for all v in V,u >= v.

incomparable

When a <> b, a and b are incomparable,

itemType

The ·atomic· or ·union·datatype that participates in the definition of a ·list· datatype is known as the itemType of that ·list· datatype.

lexical space

Alexical space is the set of valid _literals_for a datatype.

list

Listdatatypes are those having values each of which consists of a finite-length (possibly empty) sequence of values of an·atomic· datatype.

match

match

may

may

memberTypes

The datatypes that participate in the definition of a ·union· datatype are known as thememberTypes of that ·union· datatype.

minimally conforming

Minimally conforming processors ·must·completely and correctly implement the ·Constraint on Schemas· and·Validation Rule·.

must

must

non-numeric

A datatype whose values are not ·numeric· is said to benon-numeric.

numeric

A datatype is said to benumeric if its values are conceptually quantities (in some mathematical number system).

order-relation

Anorder relation on a ·value space·is a mathematical relation that imposes a·total order· or a ·partial order· on the members of the ·value space·.

ordered

A·value space·, and hence a datatype, is said to beordered if there exists an·order-relation· defined for that·value space·.

partial order

A partial order is an ·order-relation·that is irreflexive, asymmetric andtransitive.

primitive

Primitivedatatypes are those that are not defined in terms of other datatypes; they exist ab initio.

regular expression

Aregular expression is composed from zero or more·branch·es, separated by | characters.

restriction

A datatype is said to be·derived· by restriction from another datatype when values for zero or more ·constraining facet·s are specified that serve to constrain its ·value space· and/or its·lexical space· to a subset of those of its·base type·.

Schema Representation Constraint

Schema Representation Constraint

total order

A total order is an ·partial order·such that for no a and _b_is it the case that a <> b.

union

Uniondatatypes are those whose ·value space·s and·lexical space·s are the union of the ·value space·s and·lexical space·s of one or more other datatypes.

user-derived

User-derived datatypes are those ·derived·datatypes that are defined by individual schema designers.

Validation Rule

Validation Rule

value space

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·.

H References

H.2 Non-normative

Character Model

Martin J. Dürst and François Yergeau, eds. Character Model for the World Wide Web. World Wide Web Consortium Working Draft. 2001. Available at:http://www.w3.org/TR/2001/WD-charmod-20010126/

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

HTML 4.01

World Wide Web Consortium. Hypertext Markup Language, version 4.01. Available at:http://www.w3.org/TR/1999/REC-html401-19991224/

IETF INTERNET-DRAFT: IRIs

M. Dürst and M. Suignard ._Internationalized Resource Identifiers_2002. Available at:http://www.w3.org/International/iri-edit/draft-duerst-iri-04.txt

International Earth Rotation Service (IERS)

International Earth Rotation Service (IERS). See http://maia.usno.navy.mil

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.

ISO 8601:1998 Draft Revision

ISO (International Organization for Standardization).Representations of dates and times, draft revision, 1998.

ISO 8601:2000 Second Edition

ISO (International Organization for Standardization).Representations of dates and times, second edition, 2000-12-15.

Perl

The Perl Programming Language. See http://www.perl.com/pub/language/info/software.html

RDF Schema

World Wide Web Consortium. _RDF Schema Specification._Available at:http://www.w3.org/TR/2000/CR-rdf-schema-20000327/

Ruby

World Wide Web Consortium. Ruby Annotation. Available at:http://www.w3.org/TR/2001/WD-ruby-20010216/

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

U.S. Naval Observatory Time Service Department

_Information about Leap Seconds_Available at:http://tycho.usno.navy.mil/leapsec.990505.html

Unicode Regular Expression Guidelines

Mark Davis. Unicode Regular Expression Guidelines, 1988. Available at: http://www.unicode.org/unicode/reports/tr18/

XML Schema Language: Part 0 Primer

World Wide Web Consortium. XML Schema Language: Part 0 Primer. Available at:http://www.w3.org/TR/2004/REC-xmlschema-0-20041028/primer.html

XSL

World Wide Web Consortium._Extensible Stylesheet Language (XSL)._Available at: http://www.w3.org/TR/2000/CR-xsl-20001121/

I Acknowledgements (non-normative)

The following have contributed material to the first edition of this specification:

Asir S. Vedamuthu, webMethods, Inc
Mark Davis, IBM

Co-editor Ashok Malhotra's work on this specification from March 1999 until February 2001 was supported by IBM. From February 2001 until May 2004 it was supported by Microsoft.

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.

At the time the first edition of this specification was published, the members of the XML Schema Working Group were:

• Jim Barnette, Defense Information Systems Agency (DISA)
• Paul V. Biron, Health Level Seven
• Don Box, DevelopMentor
• Allen Brown, Microsoft
• Lee Buck, TIBCO Extensibility
• Charles E. Campbell, Informix
• Wayne Carr, Intel
• Peter Chen, Bootstrap Alliance and LSU
• David Cleary, Progress Software
• Dan Connolly, W3C (staff contact)
• Ugo Corda, Xerox
• Roger L. Costello, MITRE
• Haavard Danielson, Progress Software
• Josef Dietl, Mozquito Technologies
• David Ezell, Hewlett-Packard Company
• Alexander Falk, Altova GmbH
• David Fallside, IBM
• Dan Fox, Defense Logistics Information Service (DLIS)
• Matthew Fuchs, Commerce One
• Andrew Goodchild, Distributed Systems Technology Centre (DSTC Pty Ltd)
• Paul Grosso, Arbortext, Inc
• Martin Gudgin, DevelopMentor
• Dave Hollander, Contivo, Inc (co-chair)
• Mary Holstege, Invited Expert
• Jane Hunter, Distributed Systems Technology Centre (DSTC Pty Ltd)
• Rick Jelliffe, Academia Sinica
• Simon Johnston, Rational Software
• Bob Lojek, Mozquito Technologies
• Ashok Malhotra, Microsoft
• Lisa Martin, IBM
• Noah Mendelsohn, Lotus Development Corporation
• Adrian Michel, Commerce One
• Alex Milowski, Invited Expert
• Don Mullen, TIBCO Extensibility
• Dave Peterson, Graphic Communications Association
• Jonathan Robie, Software AG
• Eric Sedlar, Oracle Corp.
• C. M. Sperberg-McQueen, W3C (co-chair)
• Bob Streich, Calico Commerce
• William K. Stumbo, Xerox
• Henry S. Thompson, University of Edinburgh
• Mark Tucker, Health Level Seven
• Asir S. Vedamuthu, webMethods, Inc
• Priscilla Walmsley, XMLSolutions
• Norm Walsh, Sun Microsystems
• Aki Yoshida, SAP AG
• Kongyi Zhou, Oracle Corp.

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
• David Beech, Oracle Corp.
• Gabe Beged-Dov, Rogue Wave Software
• Greg Bumgardner, Rogue Wave Software
• Dean Burson, Lotus Development Corporation
• Mike Cokus, MITRE
• Andrew Eisenberg, Progress Software
• 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)
• Andrew Layman, Microsoft
• Dmitry Lenkov, Hewlett-Packard Company
• John McCarthy, Lawrence Berkeley National Laboratory
• Murata Makoto, Xerox
• Eve Maler, Sun Microsystems
• Murray Maloney, Muzmo Communication, acting for Commerce One
• Chris Olds, Wall Data
• Frank Olken, Lawrence Berkeley National Laboratory
• Shriram Revankar, Xerox
• Mark Reinhold, Sun Microsystems
• John C. Schneider, MITRE
• Lew Shannon, NCR
• William Shea, Merrill Lynch
• Ralph Swick, W3C
• Tony Stewart, Rivcom
• Matt Timmermans, Microstar
• Jim Trezzo, Oracle Corp.
• Steph Tryphonas, Microstar

The lists given above pertain to the first edition. At the time work on this second edition was completed, the membership of the Working Group was:

• Leonid Arbouzov, Sun Microsystems
• Jim Barnette, Defense Information Systems Agency (DISA)
• Paul V. Biron, Health Level Seven
• Allen Brown, Microsoft
• Charles E. Campbell, Invited expert
• Peter Chen, Invited expert
• Tony Cincotta, NIST
• David Ezell, National Association of Convenience Stores
• Matthew Fuchs, Invited expert
• Sandy Gao, IBM
• Andrew Goodchild, Distributed Systems Technology Centre (DSTC Pty Ltd)
• Xan Gregg, Invited expert
• Mary Holstege, Mark Logic
• Mario Jeckle, DaimlerChrysler
• Marcel Jemio, Data Interchange Standards Association
• Kohsuke Kawaguchi, Sun Microsystems
• Ashok Malhotra, Invited expert
• Lisa Martin, IBM
• Jim Melton, Oracle Corp
• Noah Mendelsohn, IBM
• Dave Peterson, Invited expert
• Anli Shundi, TIBCO Extensibility
• C. M. Sperberg-McQueen, W3C (co-chair)
• Hoylen Sue, Distributed Systems Technology Centre (DSTC Pty Ltd)
• Henry S. Thompson, University of Edinburgh
• Asir S. Vedamuthu, webMethods, Inc
• Priscilla Walmsley, Invited expert
• Kongyi Zhou, Oracle Corp.

We note with sadness the accidental death of Mario Jeckle shortly after the completion of work on this document. In addition to those named above, several people served on the Working Group during the development of this second edition:

• Oriol Carbo, University of Edinburgh
• Tyng-Ruey Chuang, Academia Sinica
• Joey Coyle, Health Level 7
• Tim Ewald, DevelopMentor
• Nelson Hung, Corel
• Melanie Kudela, Uniform Code Council
• Matthew MacKenzie, XML Global
• Cliff Schmidt, Microsoft
• John Stanton, Defense Information Systems Agency
• John Tebbutt, NIST
• Ross Thompson, Contivo
• Scott Vorthmann, TIBCO Extensibility