DRAFT

For XML Schema

This is three sections of the XML Schema CR with revised markup.

• 2.4 Conformance, illustrating definitions
• 4.1 Datatype definition, illustrating a schema component, meaningful links, a table, a constraint on schemas, and a validation rule
• 5.2.5 enumeration, illustrating an XML representation summary and an example

There is a plain version.

Notes

• To do: assign a unique XHTML font or phrase element and CSS property to each type of keyword in the XML Schema syntax.
• In the colored version, the example background now goes gray in 8-bit, rather than purple as the Primer and part 2 do now.
• Block headings should be h1-h6 headings and table captions, but because constraints and components are under different levels, they are all strong p's.
• The big table in 4.1 is 5k vs. 18k for the original.
• The eight paragraphs preceding that table now have about 25 meaningful links, vs. 83 in the original.

$Revision: 1.3 $ of $Date: 2001/01/08 05:16:40 $ by $Author: slesch $

4.1 Datatype definition

Datatype definitions provide for:

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

The datatype 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 an schema.

If {variety} is atomic then the value space of the datatype defined will be a subset of the value space of {base type definition} (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 {itemType definition}. If {variety} is union then the value space of the datatype defined will be the union of the value spaces of each datatype in {memberType definitions}.

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

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

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

If {variety} is atomic then bounded is true and cardinality is finite if one of minInclusive or minExclusive and one of maxInclusive or maxExclusive are among {facets}, otherwise bounded is false and cardinality is countably infinite, numeric and ordered are inherited from {base type definition}.

If {variety} is list then bounded is true and cardinality is finite if length or both of minLength and maxLength are among {facets}, otherwise bounded is false and cardinality is countably infinite, numeric and ordered are false.

If {variety} is union then bounded is true if every member of {memberType definitions} is bounded and all members of {memberType definitions} share a common ancestor and is false otherwise, cardinality is finite if the cardinality of every member of {memberType definitions} is finite and is countably infinite otherwise, ordered is true if every member of {memberType definitions} is ordered and all members of {memberType definitions} share a common ancestor and is false otherwise, numeric are true if every member of {memberType definitions} is numeric and is false otherwise.

5.2.5 enumeration

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

<enumeration
  id = ID
  value = string
  fixed = boolean : false
  {any attributes with non-schema namespace. . .}>
  Content: (annotation?)
</enumeration>

The following example is a datatype definition for a user-derived datatype which limits the values of dates to the three US holidays enumerated. This datatype definition would appear in a schema authored by an "end-user" and shows how to define a datatype by enumerating the values in its value space. The enumerated values must be type-valid literals for the base type.

<simpleType name='holidays'>
    <annotation>
        <documentation>some US holidays</documentation>
    </annotation>
    <restriction base='recurringDate'>
      <enumeration value='--01-01'>
        <annotation>
            <documentation>New Year's day</documentation>
        </annotation>
      </enumeration>
      <enumeration value='--07-04'>
        <annotation>
            <documentation>4th of July</documentation>
        </annotation>
      </enumeration>
      <enumeration value='--12-25'>
        <annotation>
            <documentation>Christmas</documentation>
        </annotation>
      </enumeration>
    </restriction>  
</simpleType>