CODEWITHSUNDEEP
xmlxsd
Daniel
Daniel

Reputation: 10245

XML Schema: extensible container element

I am trying to create a schema for a document that will have multiple namespaces. Something like this:

<?xml version="1.0"?>
<parent xmlns="http://myNamespace"
        xmlns:c1="http://someone/elses/namespace"
        xmlns:c2="http://yet/another/persons/namespace">

    <c1:child name="Jack"/>
    <c2:child name="Jill"/>
</parent>

This is what I have in my schema so far:

<xs:element name="parent" type="Parent"/>

<xs:complexType name="Parent">
    <!-- don't know what to put here -->
</xs:complexType>

<!-- The type that child elements must extend -->           
<xs:complexType name="Child" abstract="true">
    <xs:attribute name="name" type="xs:string"/>
</xs:complexType>

The plan is for others to be able to create documents with arbitrary child elements, as long as those child elements extends my Child type. My question is: how can I restrict the <parent> element such that it can only contain elements whose types are extensions of the Child type?

Upvotes: 1

Views: 1269

Answers (2)

Daniel
Daniel

Reputation: 10245

I found the answer here: XML Schemas: Best Practices - Variable Content Containers.

Apparently you can declare <element>s as abstract. A solution is as follows:

<xs:element name="parent" type="Parent"/>

<xs:element name="child" abstract="true"/>

<xs:complexType name="Parent">
    <xs:sequence>
        <xs:element ref="child" maxOccurs="unbounded"/>
    </xs:sequence>
</xs:complexType>

<xs:complexType name="Child" abstract="true">
    <xs:attribute name="name" type="xs:string"/>
</xs:complexType>

Other schemas can then define their own child types like this:

<xs:element name="child-one" substitutionGroup="child" type="ChildOne"/>

<xs:element name="child-two" substitutionGroup="child" type="ChildTwo"/>

<xs:complexType name="ChildOne">
    <xs:complexContent>
        <xs:extension base="Child"/>
    </xs:complexContent>
</xs:complexType>

<xs:complexType name="ChildTwo">
    <xs:complexContent>
        <xs:extension base="Child"/>
    </xs:complexContent>
</xs:complexType>

We can then have this as a valid document:

<parent>
    <c1:child-one/>
    <c1:child-two/>
</parent>

Upvotes: 1

James Jithin
James Jithin

Reputation: 10555

Please find the link below. This tells how inherit the elements.

http://www.ibm.com/developerworks/library/x-flexschema/

Upvotes: 0

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