CODEWITHSUNDEEP
xmlxsdxsd-validation
Lorelorelore
Lorelorelore

Reputation: 3393

XSD Unique Constraint on nested elements

I have the following XML file:

<?xml version="1.0" encoding="UTF-8" ?>
<catalog>
<chainList>
    <chain chainName="Chain">
        <handlerList>
            <handler handlerName="This is a name">com.lorescianatico.chain.handler.DummyHandler</handler>
            <handler handlerName="This is another name">com.lorescianatico.chain.handler.AnotherDummyHandler</handler>
        </handlerList>
    </chain>
    <chain chainName="AnotherChain">
        <handlerList>
            <handler handlerName="This is a name">com.lorescianatico.chain.handler.DummyHandler</handler>
            <handler handlerName="This is another name">com.lorescianatico.chain.handler.AnotherDummyHandler</handler>
        </handlerList>
    </chain>
</chainList>
</catalog>

I need to perform a validation using an XSD Schema. The schema I defined is the following:

<?xml version="1.0" encoding="UTF-8" ?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="catalog">
    <xs:complexType>
        <xs:sequence>
            <xs:element name="chainList" minOccurs="1" maxOccurs="1">
                <xs:complexType >
                    <xs:sequence>
                        <xs:element name="chain" minOccurs="0" maxOccurs="unbounded" type="chain"/>
                    </xs:sequence>
                </xs:complexType>
                <xs:unique name="uniqueChainName">
                    <xs:selector xpath="."/>
                    <xs:field xpath="chain/@chainName"/>
                </xs:unique>
            </xs:element>
        </xs:sequence>
        <xs:attribute name="catalogName" type="xs:string"/>
    </xs:complexType>
</xs:element>

<xs:complexType name="chain">
    <xs:sequence>
        <xs:element name="handlerList" minOccurs="1" maxOccurs="1">
            <xs:complexType>
                <xs:sequence>
                    <xs:element name="handler" minOccurs="1" maxOccurs="unbounded" type="handler"/>
                </xs:sequence>
            </xs:complexType>
            <xs:unique name="uniqueHandlerClass">
                <xs:selector xpath="."/>
                <xs:field xpath="handler"/>
            </xs:unique>
            <xs:unique name="uniqueHandlerName">
                <xs:selector xpath="."/>
                <xs:field xpath="handler/@handlerName"/>
            </xs:unique>
        </xs:element>
    </xs:sequence>
    <xs:attribute name="chainName" use="required" type="xs:string"/>
</xs:complexType>

<xs:complexType name="handler">
    <xs:simpleContent>
        <xs:extension base="xs:string">
            <xs:attribute name="handlerName" type="xs:string" use="required"/>
        </xs:extension>
    </xs:simpleContent>
</xs:complexType>
</xs:schema>

Now, if you test this xml with the schema I have pasted, validation fails beacause I defined the same handler value in different chains. Is there a way for defining the unique constraint to check if a value is unique only in a sub-xml? Like a sort of scope for the XPath query for defining unique constraint? I want the attribute handlerName and the value of handler to be unique only within the same chain.

Thanks in advance.

Upvotes: 1

Views: 594

Answers (1)

Lorelorelore
Lorelorelore

Reputation: 3393

Sometimes you just need to stop and think. After few hours I found the solution:

<xs:unique name="uniqueHandlerName">
     <xs:selector xpath="handler"/>
     <xs:field xpath="@handlerName"/>
</xs:unique>

Writing in this way the constraint worked for me.

Upvotes: 1

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