Hi, You don't need XML Schema 1.1 for that. You can use xs:unique (add it to the end of your Item xs:element): <xs:unique name="unique1"> <xs:selector xpath="a|b|c|d"/> <xs:field xpath="@id"/> </xs:unique> Alternatively you could use xs:ID as the type of the "id" attribute, but that also means you would have to use in the XML instance IDs that begin with a letter or an '_'. e.g. XML schema <xs:attribute name="id" type="xs:ID"/> <Item> <c id="a0"/> <a id="_1"/> ... Regards, Adrian Adrian Buza oXygen XML Editor and Author Support Tel: +1-650-352-1250 ext.202 Fax: +40-251-461482 support@oxygenxml.com http://www.oxygenxml.com Olumide wrote:

Is it possible to use XML 1.1 schema to verify that that elements in a document contain unique Ids. See For example the attached test XML document and Schema.

Thanks.

-------------- XML Document --------------

<?xml version="1.0" encoding="UTF-8"?> <Item> <c id="0"/> <a id="1"/> <a id="2"/> <b id="3"/> <a id="4"/> <b id="0"/> <d id="6"/> <d id="7"/> <b id="3"/> <c id="1"/> </Item>

-------------- XML 1.1 Schema --------------

<?xml version="1.0" encoding="UTF-8"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"> <xs:element name="Item"> <xs:complexType> <xs:sequence maxOccurs="unbounded"> <xs:choice>

<xs:element name="a"> <xs:complexType> <xs:attribute name="id" use="required"/> </xs:complexType> </xs:element>

<xs:element name="b"> <xs:complexType> <xs:attribute name="id" use="required"/> </xs:complexType> </xs:element>

<xs:element name="c"> <xs:complexType> <xs:attribute name="id" use="required"/> </xs:complexType> </xs:element>

<xs:element name="d"> <xs:complexType> <xs:attribute name="id" use="required"/> </xs:complexType> </xs:element>

</xs:choice> </xs:sequence> </xs:complexType> </xs:element> </xs:schema> _______________________________________________ oXygen-user mailing list oXygen-user@oxygenxml.com http://www.oxygenxml.com/mailman/listinfo/oxygen-user