Forcing a parent tag to have at least one child via an XML schema

I have a document that includes info similar to:

<cat>
<name>Tiddles</name>
<color>Purple</color>
<age>12</age>
<ageInCatYears>84</ageInCatYears>
</cat>

ALL elements (including <cat>) are optional. However, <catshould not exist
unless at least one of it children does.

How can I specific via an XML schema that <catshould not exist unless it
has at least one child?

re: Forcing a parent tag to have at least one child via an XML schema

On Oct 3, 5:37*pm, "Susan Harris" <susanbharris1...@yahoo.comwrote:I haven't check the Schema spec deeply, but I feel this might not be
possible with XSD 1.0. But it should be possible with the upcoming XSD
1.1 schema language (using the assertions feature).

With XSD 1.1, this should likely work:

<xs:element name="cat">
<xs:complexType>
<xs:sequence>
<xs:element name="name" type="xs:string" minOccurs="0"
maxOccurs="1" />
<xs:element name="color" type="xs:string" minOccurs="0"
maxOccurs="1" />
<xs:element name="age" type="xs:integer" minOccurs="0"
maxOccurs="1" />
<xs:element name="ageInCatYears" type="xs:string"
minOccurs="0" maxOccurs="1" />
</xs:sequence>
<xs:assert test="count(*) &gt; 0" />
</xs:complexType>
</xs:element>

re: Forcing a parent tag to have at least one child via an XML schema

Susan Harris wrote:
<xs:element name="cat">
<xs:complexType>
<xs:choice maxOccurs="unbounded">
<xs:element name="name" type="xs:string"/>
<xs:element name="color" type="xs:string"/>
<xs:element name="age" type="xs:int"/>
<xs:element name="ageInCatYears" type="xs:int"/>
</xs:choice>
</xs:complexType>
</xs:element>

would suffice to ensure that the 'cat' element has at least one of the
child elements listed in the choice. On the other hand the above
definition would allow several 'name' or 'color' or 'age' elements so I
doubt you want that construct.

So whether there is a solution depends on the other constraints you want
to put on the children of 'cat'.

--

Martin Honnen
http://JavaScript.FAQTs.com/