Come rendere facoltativo un elemento nello schema XML?

Question

Così ho preso questo schema XML:

<?xml version="1.0"?> <xs:schema version="1.0" 
      xmlns:xs="http://www.w3.org/2001/XMLSchema" 
      elementFormDefault="qualified"> 
    <xs:element name="request"> 
     <xs:complexType> 
      <xs:sequence> 
       <xs:element name="amenity"> 
        <xs:complexType> 
         <xs:sequence> 
          <xs:element name="description" type="xs:string" /> 
         </xs:sequence> 
        </xs:complexType> 
       </xs:element> 
      </xs:sequence> 
     </xs:complexType> 
    </xs:element> </xs:schema> 

Come faccio a fare l'elemento descrizione facoltativa? Quindi, sia XML che l'elemento description e senza verranno validati rispetto all'XSD.

Answer 1

Prova questa

<xs:element name="description" type="xs:string" minOccurs="0" maxOccurs="1" /> 

se si desidera 0 o 1 elementi "Descrizione", o

<xs:element name="description" type="xs:string" minOccurs="0" maxOccurs="unbounded" /> 

se si desidera 0 al numero di infinità di elementi "Descrizione".

Answer 2

impostare l'attributo minOccurs-0 nello schema in questo modo:

<?xml version="1.0"?> 
    <xs:schema version="1.0" xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"> 
    <xs:element name="request"> 
     <xs:complexType> 
      <xs:sequence> 
       <xs:element name="amenity"> 
        <xs:complexType> 
         <xs:sequence> 
          <xs:element name="description" type="xs:string" minOccurs="0" /> 
         </xs:sequence> 
        </xs:complexType> 
       </xs:element> 
      </xs:sequence> 
     </xs:complexType> 
    </xs:element> </xs:schema>