ZVON > Tutorials > XML Schema and Relax NG Tutorial
Intro / Search / ZVON
Index | >> Example 4 / 10 << | Prev | Next |
Contents > Simple types > Element is either a fixed string or an integer

Element is either a fixed string or an integer

  1. XML Schema
  2. Relax NG
XML Schema keys: union
Relax NG keys: choice, param

1. XML Schema

Now, we want the element "root" to be either an integer or a string "N/A". We will make a union from an "integer" type and "string" type.

Valid document


<root xsi:noNamespaceSchemaLocation="correct_0.xsd" xmlns="" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >50</root>

Valid document


<root xsi:noNamespaceSchemaLocation="correct_0.xsd" xmlns="" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >N/A</root>

Invalid document


<root xsi:noNamespaceSchemaLocation="correct_0.xsd" xmlns="" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" >#REF!</root>

Correct XML Schema (correct_0.xsd)


<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" >

  <xsd:element name="root">
    <xsd:simpleType>
      <xsd:union>
        <xsd:simpleType>
          <xsd:restriction base="xsd:integer"/>
        </xsd:simpleType>
        <xsd:simpleType>
          <xsd:restriction base="xsd:string">
            <xsd:enumeration value="N/A"/>
          </xsd:restriction>
        </xsd:simpleType>
      </xsd:union>
    </xsd:simpleType>
  </xsd:element>
</xsd:schema>

2. Relax NG

As in previous example, we will use the "choice" element.

Valid document


<root xmlns="">50</root>

Valid document


<root xmlns="">N/A</root>

Invalid document


<root xmlns="">#REF!</root>

Correct Relax NG schema (correctRelax_0.rng)


<grammar datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes" xmlns="http://relaxng.org/ns/structure/1.0" >

  <start>
    <element>
      <name ns="">root</name>
      <choice>
        <data type="integer"/>
        <value>N/A</value>
      </choice>
    </element>
  </start>
</grammar>