lesson9: XSD Complex Types Indicators

msi_333 · **Posted:** Fri Mar 06, 2009 8:08 pm

XSD Complex Types Indicators :

There are seven indicators in XSD. There are three indicator groups.
1. Order indicators :
Define elements order inside your complex type.

Any indicator
Elements can appear in any order. And all must appears.

Code:

<xs:element name="student">
  <xs:complexType>
    <xs:all>
      <xs:element name="name" type="xs:string"/>
      <xs:element name="age" type="xs:integer"/>
    </xs:all>
  </xs:complexType>
</xs:element>
 

Choice Indicator
Only one element of elements inside <choice> can appear.

Code:

<xs:element name="human">
  <xs:complexType>
    <xs:choice>
      <xs:element name="man" type="manType"/>
      <xs:element name="women" type="womenType"/>
    </xs:choice>
  </xs:complexType>
</xs:element>

Sequence Indicator
Elements should appear in the same order it was defined.

Code:

<xs:element name="student">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="name" type="xs:string"/>
      <xs:element name="age" type="xs:integer"/>
    </xs:sequence>
  </xs:complexType>
</xs:element>

2. Occurrence Indicators
Define the number of times an element occurs. maxOccurs & minOccurs attributes are used to define occurrence .Both equal 1 by default.

maxOccurs Indicator:
Define the Maximum number of element occurs.

Code:

 <xs:element name="department">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="Professor" type="xs:string" maxOccurs="unbounded"/>
      <xs:element name="Subject" type="xs:string" maxOccurs="50"
  />
    </xs:sequence>
  </xs:complexType>
</xs:element>

Note: you can set your limits to unlimited. You use maxOccurs="unbounded".

Code:

<?xml version="1.0" encoding="ISO-8859-1"?>

<department>
<Professor>Jozef Philp</ Professor>
<Professor>Amr Ali</ Professor>
<Professor>Tom Philp</ Professor>
<Subject>Course1</Subject>
<Subject> Course2</Subject>
<Subject> Course3</Subject>
<Subject> Course4</Subject>
</department>

As you can above. The department has many professors and many subjects. Same cases to minOccurs attribute.

minOccurs Indicator:
Define the minimum number of element occurs.

3.Group Indicators
Allow you to define a set of related elements and attributes.

Elements groups:
For example look for the following XSD.

Code:

<xs:group name="studentgroup">
  <xs:sequence>
    <xs:element name="name" type="xs:string"/>
    <xs:element name="age" type="xs:integer"/>
    <xs:element name="gpa" type="xs:string"/>
  </xs:sequence>
</xs:group>

You can define your element group and reference to it from other definition.

Code:

<xs:group name="studentgroup">
  <xs:sequence>
    <xs:element name="name" type="xs:string"/>
    <xs:element name="age" type="xs:integer"/>
    <xs:element name="gpa" type="xs:string"/>
  </xs:sequence>
</xs:group>

<xs:element name="student" type="studentmoreType"/>
<xs:complexType name="studentmoreType">
  <xs:sequence>
    <xs:group ref="studentgroup"/>
    <xs:element name="Address" type="xs:string"/>
  </xs:sequence>
</xs:complexType>

Attribute Groups:

Code:

<xs:attributeGroup name=" studentgroup">
  <xs:attribute name="name" type="xs:string"/>
  <xs:attribute name="age" type="xs:integer"/>
  <xs:attribute name="gpa" type="xs:string"/>
</xs:attributeGroup>

You can define your attribute group and reference to it from other definition.

Code:

<xs:attributeGroup name="studentgroup">
  <xs:attribute name="name" type="xs:string"/>
  <xs:attribute name="age" type="xs:integer"/>
  <xs:attribute name="gpa" type="xs:string"/>
</xs:attributeGroup>

<xs:element name="student">
  <xs:complexType>
    <xs:attributeGroup ref="studentgroup"/>
  </xs:complexType>
</xs:element>

lesson9: XSD Complex Types Indicators

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