XSD: How to validate the XML file according to value of some tag?

Question

I was trying to validate this XML file ... where if

1. is \"Y\" then must appear

2. if

Answer 1

It's a known fact that this is a handycap of XML schema. But I would appreciate your approach of trying the <choice> tag. It could be successful if your conditions were something like this:

1. If <tag1> is required and appears first then <tag2> isn't required (and appears as second tag)
2. If <tag2> is required and appears first then <tag1> isn't required (and appears as second)

The code is:

<xs:element name="parent">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="a" maxOccurs="unbounded">
        <xs:complexType>
          <xs:choice>
            <xs:sequence>
              <xs:element name="tag1" type="xs:boolean" />
              <xs:element name="tag2" type="xs:string" minOccurs="0" />
            </xs:sequence>
            <xs:sequence>
              <xs:element name="tag2" type="xs:string" />
              <xs:element name="tag1" type="xs:boolean" minOccurs="0" />
            </xs:sequence>
          </xs:choice>
        </xs:complexType>
      </xs:element>
    </xs:sequence>
  </xs:complexType>
</xs:element>

Answer 2

You cannot validate things like that with XSD.

XML schema is not designed and not intended to check "intra-tag" relationships, e.g. "tag2 must be present if tag1's value is 'Y'" - just cannot be done, sorry.

If you need to check these kind of conditions, you'll have to look at Schematron to do that.

Answer 3

Its not possible with XSD .. But by the way you can work around something like Infant-programmer if the requirement is bit comfortable as shown in her example ..

Answer 4

Unfortunately this problem cannot be fixed using XSD. The reason is that XSD can only be used to define the structure (syntax) of XML-Files. What you would like to do is to couple the syntax to some semantic properties (some TAG must have a certain content to decide on the syntax of some TAGS nearby).