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Definitive XML Schema
Overview
Table of Contents
Sample Chapter
Examples
1. Intro
2. Quick tour
3. Namespaces
4. Include/Import
5. Instances
6. Annotations
7. Element Decls
8. Attribute Decls
9. Simple types
10. Regexes
11. Union/List types
12. Built-in types
13. Complex types
14. Type derivation
15. Groups
16. Subst. groups
17. ID constraints
18. Redefines
19. DTDs topics
20. Naming
21. Extensibility
Errata
XQuery
Web Service Contract Design
XML in Office 2003
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Definitive XML Schema

Definitive XML Schema

Priscilla Walmsley (pwalmsley@datypic.com)
1st edition (December 7, 2001)
Prentice Hall PTR; ISBN: 0130655678 		Amazon.com
Buy at 37% off list price
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Chapter 14: Deriving complex types

Full Example

This example illustrates complex types that are derived from other specified types.

Instance (chapter14.xml) 

<items xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:noNamespaceSchemaLocation="chapter14.xsd">
  <hat routingNum="123456" effDate="2002-04-02" lang="en-US">
    <number>557</number>
    <name>Ten-Gallon Hat</name>
    <description>This is a great hat!</description>
  </hat>
  <umbrella routingNum="123" effDate="2002-04-02">
    <number>557</number>
    <name>Ten-Gallon Hat</name>
  </umbrella>
  <shirt routingNum="124" effDate="2002-04-02" sleeve="17">
    <number>557</number>
    <name>Short-Sleeved Linen Blouse</name>
    <color value="blue"/>
    <size system="US-DRESS">6</size>
  </shirt>
</items>

Schema (chapter14.xsd) 

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">

  <xs:element name="items" type="ItemsType"/>

  <xs:complexType name="ItemsType">
    <xs:choice minOccurs="0" maxOccurs="unbounded">
      <xs:element name="hat" type="ProductType"/>
      <xs:element name="umbrella" type="RestrictedProductType"/>
      <xs:element name="shirt" type="ShirtType"/>
    </xs:choice>
  </xs:complexType>

  <!--Empty Content Type-->
  <xs:complexType name="ItemType" abstract="true">
    <xs:attribute name="routingNum" type="xs:integer"/>
  </xs:complexType>

  <!--Empty Content Extension (with Attribute Extension)-->
  <xs:complexType name="ProductType">
    <xs:complexContent>
      <xs:extension base="ItemType">
        <xs:sequence>
          <xs:element name="number" type="xs:integer"/>
          <xs:element name="name" type="xs:string"/>
          <xs:element name="description"
                       type="xs:string" minOccurs="0"/>
        </xs:sequence>
        <xs:attribute name="effDate" type="xs:date"/>
        <xs:attribute name="lang" type="xs:language"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>

  <!--Complex Content Restriction-->
  <xs:complexType name="RestrictedProductType">
    <xs:complexContent>
      <xs:restriction base="ProductType">
        <xs:sequence>
          <xs:element name="number" type="xs:integer"/>
          <xs:element name="name" type="xs:token"/>
        </xs:sequence>
        <xs:attribute name="routingNum"
                       type="xs:short" use="required"/>
        <xs:attribute name="effDate"
                       type="xs:date" default="1900-01-01"/>
        <xs:attribute name="lang" use="prohibited"/>
      </xs:restriction>
    </xs:complexContent>
  </xs:complexType>

  <!--Complex Content Extension-->
  <xs:complexType name="ShirtType">
    <xs:complexContent>
      <xs:extension base="RestrictedProductType">
        <xs:choice maxOccurs="unbounded">
          <xs:element name="size" type="SmallSizeType"/>
          <xs:element name="color" type="ColorType"/>
        </xs:choice>
        <xs:attribute name="sleeve" type="xs:integer"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>

  <!--Simple Content Extension-->
  <xs:complexType name="SizeType">
    <xs:simpleContent>
      <xs:extension base="xs:integer">
        <xs:attribute name="system" type="xs:token"/>
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <!--Simple Content Restriction-->
  <xs:complexType name="SmallSizeType">
    <xs:simpleContent>
      <xs:restriction base="SizeType">
        <xs:minInclusive value="2"/>
        <xs:maxInclusive value="6"/>
        <xs:attribute  name="system" type="xs:token"
                        use="required"/>
      </xs:restriction>
    </xs:simpleContent>
  </xs:complexType>

  <xs:complexType name="ColorType">
    <xs:attribute name="value" type="xs:string"/>
  </xs:complexType>

</xs:schema>

Book Examples

Example 14-1. Simple content extension 

<xsd:complexType name="SizeType">
  <xsd:simpleContent>
    <xsd:extension base="xsd:integer">
      <xsd:attribute name="system" type="xsd:token"/>
    </xsd:extension>
  </xsd:simpleContent>
</xsd:complexType>
<size system="US-DRESS">10</size>

Example 14-2. Complex content extension 

<xsd:complexType name="ProductType">
  <xsd:sequence>
    <xsd:element name="number" type="ProdNumType"/>
    <xsd:element name="name" type="xsd:string"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="ShirtType">
  <xsd:complexContent>
    <xsd:extension base="ProductType">
      <xsd:choice maxOccurs="unbounded">
        <xsd:element name="size" type="SizeType"/>
        <xsd:element name="color" type="ColorType"/>
      </xsd:choice>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

Example 14-3. Effective content model of ShirtType 

<xsd:complexType name="ShirtType">
  <xsd:sequence>
    <xsd:sequence>
      <xsd:element name="number" type="ProdNumType"/>
      <xsd:element name="name" type="xsd:string"/>
    </xsd:sequence>
    <xsd:choice maxOccurs="unbounded">
      <xsd:element name="size" type="SizeType"/>
      <xsd:element name="color" type="ColorType"/>
    </xsd:choice>
  </xsd:sequence>
</xsd:complexType>

Example 14-4. choice group extension 

<xsd:complexType name="ItemsType">
  <xsd:choice maxOccurs="unbounded">
    <xsd:element ref="shirt"/>
    <xsd:element ref="hat"/>
    <xsd:element ref="umbrella"/>
  </xsd:choice>
</xsd:complexType>

<xsd:complexType name="ExpandedItemsType">
  <xsd:complexContent>
    <xsd:extension base="ItemsType">
      <xsd:choice maxOccurs="unbounded">
        <xsd:element ref="sweater"/>
        <xsd:element ref="suit"/>
      </xsd:choice>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

Example 14-5. Mixed content extension 

<xsd:complexType name="LetterType" mixed="true">
  <xsd:sequence>
    <xsd:element name="custName" type="PersonNameType"/>
    <xsd:element name="prodName" type="xsd:string"/>
    <xsd:element name="prodSize" type="SizeType"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="ExtendedLetterType" mixed="true">
  <xsd:complexContent>
    <xsd:extension base="LetterType">
      <xsd:sequence>
        <xsd:element name="prodNum" type="ProdNumType"/>
      </xsd:sequence>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

Example 14-6. Empty content extension 

<xsd:complexType name="ItemType">
  <xsd:attribute name="routingNum" type="xsd:integer"/>
</xsd:complexType>

<xsd:complexType name="ProductType">
  <xsd:complexContent>
    <xsd:extension base="ItemType">
      <xsd:sequence>
        <xsd:element name="number" type="ProdNumType"/>
        <xsd:element name="name" type="xsd:string"/>
      </xsd:sequence>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

Example 14-7. Attribute extension 

<xsd:complexType name="ItemType">
  <xsd:attribute name="id" type="xsd:ID" use="required"/>
  <xsd:attribute ref="xml:lang"/>
</xsd:complexType>

<xsd:complexType name="ProductType">
  <xsd:complexContent>
    <xsd:extension base="ItemType">
      <xsd:attribute name="effDate" type="xsd:date"/>
      <xsd:attribute name="lang" type="xsd:language"/>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>
<product id="prod557"
  xml:lang="en"
  lang="en"
  effDate="2001-04-02"/>

Example 14-8. Attribute wildcard extension 

<xsd:complexType name="BaseType">
  <xsd:anyAttribute processContents="lax"
                    namespace="##local
                               http://example.org/prod"/>
</xsd:complexType>

<xsd:complexType name="DerivedType">
  <xsd:complexContent>
    <xsd:extension base="BaseType">
      <xsd:anyAttribute processContents="strict"
                        namespace="##targetNamespace
                                   http://www.w3.org/1999/xhtml"/>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

Example 14-9. Effective attribute wildcard 

<xsd:complexType name="DerivedType">
    <xsd:anyAttribute processContents="strict"
                      namespace="##local
                                 http://example.org/prod
                                 ##targetNamespace
                                 http://www.w3.org/1999/xhtml"/>
</xsd:complexType>

Example 14-10. Simple content restriction 

<xsd:complexType name="SmallSizeType">
  <xsd:simpleContent>
    <xsd:restriction base="SizeType">
      <xsd:minInclusive value="2"/>
      <xsd:maxInclusive value="6"/>
      <xsd:attribute name="system" type="xsd:token"
                     use="required"/>
    </xsd:restriction>
  </xsd:simpleContent>
</xsd:complexType>

Example 14-11. Complex content restriction 

<xsd:complexType name="ProductType">
  <xsd:sequence>
    <xsd:element name="number" type="ProdNumType"/>
    <xsd:element name="name" type="xsd:string"/>
    <xsd:element name="size" type="SizeType" minOccurs="0"/>
    <xsd:element name="color" type="ColorType" minOccurs="0"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="RestrictedProductType">
  <xsd:complexContent>
    <xsd:restriction base="ProductType">
      <xsd:sequence>
        <xsd:element name="number" type="ProdNumType"/>
        <xsd:element name="name" type="xsd:string"/>
      </xsd:sequence>
    </xsd:restriction>
  </xsd:complexContent>
</xsd:complexType>

Example 14-12. Eliminating meaningless groups 

<xsd:sequence>
  <xsd:sequence>
    <xsd:element name="a"/>
    <xsd:element name="b"/>
  </xsd:sequence>
</xsd:sequence>
<xsd:sequence>
  <xsd:element name="a"/>
  <xsd:element name="b"/>
</xsd:sequence>

Example 14-13. Restricting element declarations 

<xsd:sequence>
  <xsd:element name="a" maxOccurs="3"/>
  <xsd:element name="b" fixed="bValue"/>
  <xsd:element name="c" type="xsd:string"/>
</xsd:sequence>
<xsd:sequence>
  <xsd:element name="a" maxOccurs="2"/>
  <xsd:element name="b" fixed="bValue"/>
  <xsd:element name="c" type="xsd:token"/>
</xsd:sequence>
<xsd:sequence>
  <xsd:element name="a" maxOccurs="4"/>
  <xsd:element name="b" fixed="newValue"/>
  <xsd:element name="c" type="xsd:integer"/>
</xsd:sequence>

Example 14-14. Replacing a wildcard with element declarations 

<xsd:sequence>
  <xsd:element name="a"/>
  <xsd:any namespace="##other" maxOccurs="1"/>
</xsd:sequence>
<xsd:sequence>
  <xsd:element name="a"/>
  <xsd:element ref="otherns:b"/>
</xsd:sequence>
<xsd:sequence>
  <xsd:element name="a"/>
  <xsd:element ref="b"/>
  <xsd:element name="c"/>
</xsd:sequence>

Example 14-15. Replacing a wildcard with another wildcard 

<xsd:any namespace="urn:a:1 urn:a:2" maxOccurs="2"/>
<xsd:any namespace="urn:a:1" maxOccurs="1"/>
<xsd:any namespace="##other" maxOccurs="3"/>

Example 14-16. Replacing a group with an element declaration 

<xsd:sequence>
  <xsd:element name="a"/>
  <xsd:element name="b" minOccurs="0"/>
</xsd:sequence>
<xsd:element name="a"/>

Example 14-17. Restricting occurrence constraints of a group 

<xsd:sequence minOccurs="2" maxOccurs="5">
  <xsd:element name="a"/>
  <xsd:element name="b"/>
</xsd:sequence>
<xsd:sequence minOccurs="3" maxOccurs="4">
  <xsd:element name="a"/>
  <xsd:element name="b"/>
</xsd:sequence>
<xsd:sequence minOccurs="0" maxOccurs="6">
  <xsd:element name="a"/>
  <xsd:element name="b"/>
</xsd:sequence>

Example 14-18. Maintaining the order of the children in an all group 

<xsd:all>
  <xsd:element name="a"/>
  <xsd:element name="b" minOccurs="0"/>
  <xsd:element name="c"/>
</xsd:all>
<xsd:all>
  <xsd:element name="a"/>
  <xsd:element name="c"/>
</xsd:all>
<xsd:all>
  <xsd:element name="c"/>
  <xsd:element name="a"/>
</xsd:all>

Example 14-19. Restricting an all group 

<xsd:all>
  <xsd:element name="a"/>
  <xsd:element name="b" minOccurs="0"/>
  <xsd:element name="c"/>
</xsd:all>
<xsd:all>
  <xsd:element name="a"/>
  <xsd:element name="c"/>
</xsd:all>
<xsd:all>
  <xsd:element name="a"/>
  <xsd:element name="b"/>
</xsd:all>

Example 14-20. Restricting a choice group 

<xsd:choice>
  <xsd:element name="a"/>
  <xsd:element name="b"/>
  <xsd:element name="c"/>
</xsd:choice>
<xsd:choice>
  <xsd:element name="a"/>
  <xsd:element name="c"/>
</xsd:choice>
<xsd:choice>
  <xsd:element name="a"/>
  <xsd:element name="d"/>
</xsd:choice>

Example 14-21. Replacing an all group with a sequence group 

<xsd:all>
  <xsd:element name="a"/>
  <xsd:element name="b" minOccurs="0"/>
  <xsd:element name="c"/>
</xsd:all>
<xsd:sequence>
  <xsd:element name="a"/>
  <xsd:element name="c"/>
</xsd:sequence>
<xsd:sequence>
  <xsd:element name="a"/>
  <xsd:element name="b"/>
  <xsd:element name="c" minOccurs="2"/>
</xsd:sequence>

Example 14-22. Replacing a choice group with a sequence group 

<xsd:choice maxOccurs="2">
  <xsd:element name="a"/>
  <xsd:element name="b"/>
  <xsd:element name="c"/>
</xsd:choice>
<xsd:sequence>
  <xsd:element name="a"/>
  <xsd:element name="c"/>
</xsd:sequence>
<xsd:sequence>
  <xsd:element name="a"/>
  <xsd:element name="b"/>
  <xsd:element name="c"/>
</xsd:sequence>

Example 14-23. Mixed content restriction 

<xsd:complexType name="LetterType" mixed="true">
  <xsd:sequence>
    <xsd:element name="custName" type="PersonNameType"/>
    <xsd:element name="prodName" type="xsd:string"/>
    <xsd:element name="prodSize" type="SizeType" minOccurs="0"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="RestrictedLetterType" mixed="true">
  <xsd:complexContent>
    <xsd:restriction base="LetterType">
      <xsd:sequence>
        <xsd:element name="custName" type="PersonNameType"/>
        <xsd:element name="prodName" type="xsd:string"/>
      </xsd:sequence>
    </xsd:restriction>
  </xsd:complexContent>
</xsd:complexType>

Example 14-24. Mixed content restricted to simple content 

<xsd:complexType name="LetterType" mixed="true">
  <xsd:sequence minOccurs="0">
    <xsd:element name="custName" type="PersonNameType"/>
    <xsd:element name="prodName" type="xsd:string"/>
    <xsd:element name="prodSize" type="SizeType"/>
  </xsd:sequence>
</xsd:complexType>

<xsd:complexType name="RestrictedLetterType">
  <xsd:simpleContent>
    <xsd:restriction base="LetterType">
      <xsd:simpleType>
        <xsd:restriction base="xsd:string"/>
      </xsd:simpleType>
    </xsd:restriction>
  </xsd:simpleContent>
</xsd:complexType>

Example 14-25. Empty content restriction 

<xsd:complexType name="ItemType">
  <xsd:attribute name="routingNum" type="xsd:integer"/>
</xsd:complexType>

<xsd:complexType name="RestrictedItemType">
  <xsd:complexContent>
    <xsd:restriction base="ItemType">
      <xsd:attribute name="routingNum" type="xsd:short"/>
    </xsd:restriction>
  </xsd:complexContent>
</xsd:complexType>

Example 14-26. Legal restrictions of attributes 

<xsd:complexType name="BaseType">
      <xsd:attribute name="a" type="xsd:integer"/>
      <xsd:attribute name="b" type="xsd:string"/>
      <xsd:attribute name="c" type="xsd:string" default="c"/>
      <xsd:attribute name="d" type="xsd:string"/>
      <xsd:attribute name="e" type="xsd:string" fixed="e"/>
      <xsd:attribute name="f" type="xsd:string"/>
      <xsd:attribute name="g" type="xsd:string"/>
      <xsd:attribute name="x" type="xsd:string"/>
</xsd:complexType>

<xsd:complexType name="DerivedType">
  <xsd:complexContent>
    <xsd:restriction base="BaseType">
      <xsd:attribute name="a" type="xsd:positiveInteger"/>
      <xsd:attribute name="b" type="xsd:string" default="b"/>
      <xsd:attribute name="c" type="xsd:string" default="c2"/>
      <xsd:attribute name="d" type="xsd:string" fixed="d"/>
      <xsd:attribute name="e" type="xsd:string" fixed="e"/>
      <xsd:attribute name="f" type="xsd:string" use="required"/>
      <xsd:attribute name="g" type="xsd:string" use="prohibited"/>
    </xsd:restriction>
  </xsd:complexContent>
</xsd:complexType>

Example 14-27. Illegal attribute restrictions 

<xsd:complexType name="BaseType2">
      <xsd:attribute name="h" type="xsd:integer"/>
      <xsd:attribute name="i" type="xsd:string" fixed="i"/>
      <xsd:attribute name="j" type="xsd:string" fixed="j"/>
      <xsd:attribute name="k" type="xsd:string" use="required"/>
      <xsd:attribute name="l" type="xsd:string" use="required"/>
</xsd:complexType>

<xsd:complexType name="IllegalDerivedType">
  <xsd:complexContent>
    <xsd:restriction base="BaseType2">
      <xsd:attribute name="h" type="xsd:decimal"/>
      <xsd:attribute name="i" type="xsd:string" fixed="i2"/>
      <xsd:attribute name="j" type="xsd:string" default="j"/>
      <xsd:attribute name="k" type="xsd:string"/>
      <xsd:attribute name="l" type="xsd:string" use="prohibited"/>
      <xsd:attribute ref="pref:l"/>
      <xsd:attribute name="m" type="xsd:string"/>
    </xsd:restriction>
  </xsd:complexContent>
</xsd:complexType>

Example 14-28. Restricting an attribute wildcard 

<xsd:complexType name="BaseType">
    <xsd:anyAttribute processContents="lax" namespace="##any"/>
</xsd:complexType>

<xsd:complexType name="DerivedType">
  <xsd:complexContent>
    <xsd:restriction base="BaseType">
      <xsd:anyAttribute processContents="strict"
                        namespace="##targetNamespace
                                   http://www.w3.org/1999/xhtml"/>
    </xsd:restriction>
  </xsd:complexContent>
</xsd:complexType>

Example 14-29. Replacing an attribute wildcard by attributes 

<xsd:complexType name="BaseType">
  <xsd:anyAttribute processContents="lax" namespace="##any"/>
</xsd:complexType>

<xsd:complexType name="DerivedType">
  <xsd:complexContent>
    <xsd:restriction base="BaseType">
      <xsd:attribute name="id" type="xsd:ID" use="required"/>
      <xsd:attribute name="name" type="xsd:string"/>
    </xsd:restriction>
  </xsd:complexContent>
</xsd:complexType>

Example 14-30. A derived type 

<xsd:complexType name="ProductType">
  <xsd:sequence>
    <xsd:element name="number" type="ProdNumType"/>
    <xsd:element name="name" type="xsd:string"/>
  </xsd:sequence>
</xsd:complexType>
<xsd:element name="product" type="ProductType"/>

<xsd:complexType name="ShirtType">
  <xsd:complexContent>
    <xsd:extension base="ProductType">
      <xsd:choice maxOccurs="unbounded">
        <xsd:element name="size" type="SizeType"/>
        <xsd:element name="color" type="ColorType"/>
      </xsd:choice>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

Example 14-31. Substitution of ShirtType for ProductType 

<items xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

  <product xsi:type="ShirtType">
    <number>557</number>
    <name>Short-Sleeved Linen Blouse</name>
    <color value="blue"/>
  </product>

  <!--...-->
</items>

Example 14-32. Preventing derivation 

<xsd:complexType name="ProductType" final="#all">
  <xsd:sequence>
    <xsd:element name="number" type="ProdNumType"/>
    <xsd:element name="name" type="xsd:string"/>
  </xsd:sequence>
</xsd:complexType>

Example 14-33. Preventing substitution of derived types 

<xsd:complexType name="ProductType" block="extension">
  <xsd:sequence>
    <xsd:element name="number" type="ProdNumType"/>
    <xsd:element name="name" type="xsd:string"/>
  </xsd:sequence>
</xsd:complexType>
<xsd:element name="product" type="ProductType"/>

<xsd:complexType name="ShirtType">
  <xsd:complexContent>
    <xsd:extension base="ProductType">
      <xsd:choice maxOccurs="unbounded">
        <xsd:element name="size" type="SizeType"/>
        <xsd:element name="color" type="ColorType"/>
      </xsd:choice>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>
<xsd:element name="shirt" type="ShirtType"/>

Example 14-34. Illegal substitution of ShirtType 

<product xsi:type="ShirtType">
  <number>557</number>
  <name>Short-Sleeved Linen Blouse</name>
  <color value="blue"/>
</product>

Example 14-35. An abstract type 

<xsd:complexType name="ProductType" abstract="true">
  <xsd:sequence>
    <xsd:element name="number" type="ProdNumType"/>
    <xsd:element name="name" type="xsd:string"/>
  </xsd:sequence>
</xsd:complexType>
<xsd:element name="product" type="ProductType"/>

<xsd:complexType name="ShirtType">
  <xsd:complexContent>
    <xsd:extension base="ProductType">
      <xsd:choice maxOccurs="unbounded">
        <xsd:element name="size" type="SizeType"/>
        <xsd:element name="color" type="ColorType"/>
      </xsd:choice>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>
<xsd:element name="shirt" type="ShirtType"/>

Example 14-36. Legal instances of product and shirt 

<product xsi:type="ShirtType">
  <number>557</number>
  <name>Short-Sleeved Linen Blouse</name>
  <color value="blue"/>
</product>

<shirt>
  <number>557</number>
  <name>Short-Sleeved Linen Blouse</name>
  <color value="blue"/>
</shirt>

Example 14-37. Illegal uses of the abstract ProductType 

<product>
  <number>557</number>
  <name>Short-Sleeved Linen Blouse</name>
</product>

<product xsi:type="ProductType">
  <number>557</number>
  <name>Short-Sleeved Linen Blouse</name>
</product>