How to use XSD occurance indicators to denote at least one required

Question

I'd like to create a element that requires at least 1 child to exist, but may have multiple occurrences of one or more child.

The following examples would all be valid :

<Parent>
    <ChildA></ChildA>
    <ChildB></ChildB>
</Parent>

<Parent>
    <ChildB></ChildB>
    <ChildA></ChildA>
</Parent>

<Parent>
    <ChildB></ChildB>
    <ChildA></ChildA>
    <ChildB></ChildB>
    <ChildB></ChildB>
    <ChildB></ChildB>
    <ChildA></ChildA>
</Parent>

This would be invalid:

<Parent>
</Parent>

I found this but it doesn't seem to allow a variable number of occurrences of any particular child.

all doesn't seem to allow for more than one occurrence either

Answer 1

This XSD,

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="Parent">
    <xs:complexType>
      <xs:choice maxOccurs="unbounded">
        <xs:element name="ChildA"/>
        <xs:element name="ChildB"/>
      </xs:choice>
    </xs:complexType>
  </xs:element>
</xs:schema>

will successfully validate XML that has at least one of the listed child elements. Your valid examples will be considered valid, but not your invalid example.