CODEWITHSUNDEEP
xmlxsd
lerner1225
lerner1225

Reputation: 902

XML element occurrence

I am writing a schema for the following XML. I want to limit the occurrence of Element_E, Element_F and Element_G to '1' and Element_D can occur n number of times. I tried to use xs:sequence but it enforces the element order, xs:choice does not check the max occurrences of above elements.

Is it possible to validate the occurrence of each element in a group through XML Schema?

<?xml version="1.0" encoding="utf-8"?>
<Element_A>                     <!-- One time occurrence -->
  <Element_B>                   <!-- One time occurrence -->
    <Element_C>                 <!-- One time occurrence -->
      <Element_D />             <!-- n time occurrence -->
      <Element_D />
      <Element_D />
      <Element_E />             <!-- One time occurrence -->
      <Element_F />             <!-- One time occurrence -->
      <Element_G />             <!-- One time occurrence -->
    </Element_C>
  </Element_B>
</Element_A>

Upvotes: 0

Views: 1185

Answers (2)

kjhughes
kjhughes

Reputation: 111726

With XSD 1.0, you'll have to check such a constraint in code.

With XSD 1.1, you can use xs:assert to state count invariants:

<?xml version="1.0" encoding="utf-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           version="1.1"
           xmlns:vc="http://www.w3.org/2007/XMLSchema-versioning" vc:minVersion="1.1">

  <xs:element name="Element_A">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="Element_B">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="Element_C">
                <xs:complexType>
                  <xs:choice maxOccurs="unbounded">
                    <xs:element name="Element_D"/>
                    <xs:element name="Element_E"/>
                    <xs:element name="Element_F"/>
                    <xs:element name="Element_G"/>
                  </xs:choice>
                  <xs:assert test="    count(Element_E) = 1
                                   and count(Element_F) = 1
                                   and count(Element_G) = 1"/>
                </xs:complexType>
              </xs:element>
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

Upvotes: 1

Giorgio Minardi
Giorgio Minardi

Reputation: 2775

Have you looked into maxOccurs ?

<xsd:element ref="Element_E" maxOccurs="1"/>

http://www.w3schools.com/schema/schema_complex_indicators.asp

Upvotes: 0

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