XSD Indicators
We can control HOW elements are to be used in documents with indicators.
Indicators
There are seven indicators:
Order indicators:
- All
- Choice
- Sequence
Occurrence indicators:
- maxOccurs
- minOccurs
Group indicators:
- Group name
- attributeGroup name
Order Indicators
Order indicators are used to define the order of the elements.
All Indicator
The <all> indicator specifies that the child elements can appear in any order, and that each child element must occur only once:
<xs:element name="person">
<xs:complexType>
<xs:all>
<xs:element name="firstname" type="xs:string"/>
<xs:element name="lastname" type="xs:string"/>
</xs:all>
</xs:complexType>
</xs:element>
Note: When using the <all> indicator you can set the <minOccurs> indicator to 0 or 1 and the <maxOccurs> indicator can only be set to 1 (the <minOccurs> and <maxOccurs> are described later).
Choice Indicator
The <choice> indicator specifies that either one child element or another can occur:
<xs:element name="person">
<xs:complexType>
<xs:choice>
<xs:element name="employee" type="employee"/>
<xs:element name="member" type="member"/>
</xs:choice>
</xs:complexType>
</xs:element>
Sequence Indicator
The <sequence> indicator specifies that the child elements must appear in a specific order:
<xs:element name="person">
<xs:complexType>
<xs:sequence>
<xs:element name="firstname" type="xs:string"/>
<xs:element name="lastname" type="xs:string"/>
</xs:sequence>
</xs:complexType>
</xs:element>