How do I ensure unique element values in an XML schema?

oxygenxml, schema, xml, xsd

Solution

the schema seems ok and should detect the duplicate. may be a bug in Oxygen?

you can try this site to validate your xml : http://www.xmlvalidation.com

and you'll see it finds errors in your xmldocument:

Duplicate unique value [Book1] declared for identity constraint of element "books"

Problem

I want to ensure that there are no duplicate book titles in the following xml: ``` <?xml version="1.0" encoding="UTF-8"?> <books xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="books3.xsd"> <book> <title>Book1</title> </book> <book> <title>Book2</title> </book> <book> <title>Book1</title> <!-- duplicate should not be allowed --> </book> </books> ``` I am using the following schema: ``` <?xml version="1.0" encoding="UTF-8"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"> <xs:element name="books"> <xs:complexType> <xs:sequence> <xs:element maxOccurs="unbounded" ref="book"/> </xs:sequence> </xs:complexType> <xs:unique name="testUnique"> <xs:selector xpath="book"/> <xs:field xpath="title"/> </xs:unique> </xs:element> <xs:element name="book"> <xs:complexType> <xs:sequence> <xs:element ref="title"/> </xs:sequence> </xs:complexType> </xs:element> <xs:element name="title" type="xs:NCName"/> </xs:schema> ``` oXygen XML editor tells me this is valid when I validate. Can anybody see what I am doing wrong?

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