Question

I need your help to define a special case in XML schema: A sequence that contains two elements: ‘x’ and ‘y’ whereas:

• <x> element can appear 0 to unbound times in the sequence

• <y> element can appear 0 to 1 time in the sequence

• <x> and <y> locations can be anywhere – that is, it is possible to have unbound times the <x> element and then a single <y> element, and then unbound times the <x> element.

XML examples of this problem:

Example #1

<x>stuff</x> <y>stuff</y> <x>stuff</x> 

Example #2

<y>stuff</y> <x>stuff</x> <x>stuff</x> 

Example #3

<x>stuff</x>  <x>stuff</x> <y>stuff</y> <x>stuff</x> 

Thanks!

Answer 1

For various reasons, none of Yuval’s, Mo’s or davidsheldon’s samples work. Here’s one that does.

    <xs:complexType name='myComplexType'>     <xs:sequence>         <xs:element name='x' type='xs:string' minOccurs='0' maxOccurs='unbounded'/>         <xs:sequence minOccurs='0'>             <xs:element name='y' type='xs:string'/>             <xs:element name='x' type='xs:string' minOccurs='0' maxOccurs='unbounded'/>         </xs:sequence>     </xs:sequence>     </xs:complexType>