XML Schema - "all" compositor

Defines the occurrence of child elements without definition of their order.

May appear on the definition top level only.

The cardinality of child elements can be one at most.

Example:

<xs:complexType name="bookType"> 
 <xs:all>
   <xs:element name="title" type="xs:string"/> 
   <xs:element name="author" type="xs:string"/>
   <xs:element name="character"type="characterType" minOccurs="0" maxOccurs="1"/>
 </xs:all>
 <xs:attribute name="isbn" type="isbnType" use="required"/>
</xs:complexType>