Figure 1 DTD Type System
Type
| Description
| CDATA
| Arbitrary character data
| ID
| A name that is unique within the document
| IDREF
| A reference to an ID value in the document
| IDREFS
| A space-delimited list of IDREF values
| ENTITY
| The name of an unparsed entity declared in the DTD
| ENTITIES
| A space-delimited list of ENTITY values
| NMTOKEN
| A valid XML name
| NMTOKENS
| A space-delimited list of NMTOKEN values
| Figure 3 Complex Type Compositors
Compositor
| DTD Equivalent
| Definition
| xsd:sequence
| Comma-separated group
| An ordered sequence of contained items
| xsd:choice
| Pipe-separated group
| A choice of the contained items
| xsd:all
| None
| All of the contained items in any order
| Figure 4 Referencing Global Elements
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:tns="http://example.org/employee/"
targetNamespace="http://example.org/employee/">
<xsd:element name="employee">
<xsd:complexType>
<xsd:sequence>
<xsd:element ref="tns:name"/>
<xsd:element ref="tns:hiredate"/>
<xsd:element ref="tns:salary"/>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
<xsd:element name="name"/>
<xsd:element name="hiredate"/>
<xsd:element name="salary"/>
</xsd:schema>
Figure 5 Avoiding Namespace Prefixes
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns="http://example.org/employee/"
targetNamespace="http://example.org/employee/">
<xsd:element name="employee">
<xsd:complexType>
<xsd:sequence>
<xsd:element ref="name"/>
<xsd:element ref="hiredate"/>
<xsd:element ref="salary"/>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
<xsd:element name="name"/>
<xsd:element name="hiredate"/>
<xsd:element name="salary"/>
</xsd:schema>
Figure 6 Local Element Declarations
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://example.org/employee/">
<!-- global element declarations -->
<xsd:element name="employee">
<xsd:complexType>
<xsd:sequence>
<!-- local element declarations -->
<xsd:element name="name"/>
<xsd:element name="hiredate"/>
<xsd:element name="salary"/>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
</xsd:schema>
Figure 7 Using minOccurs/maxOccurs
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://example.org/employee/">
<xsd:element name="employee">
<xsd:complexType>
<xsd:sequence>
<xsd:sequence>
<xsd:element name="fname/>
<xsd:choice minOccurs="0">
<xsd:element name="middle"/>
<xsd:element name="mi"/>
</xsd:choice>
<xsd:element name="lname" maxOccurs="2"/>
</xsd:sequence>
<xsd:sequence minOccurs="0" maxOccurs="unbounded">
<xsd:element name="project"/>
<xsd:element name="role"/>
</xsd:sequence>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
</xsd:schema>
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