simple problem trying to specify a unique attribute with XML schema

Discussion in 'XML' started by smachin1000@gmail.com, Jul 26, 2006.

  1. Guest

    Hi All,

    In the sample schema & document below, I'd like the attribute "name" to
    be unique for all function elements under function_list. The tools I'm
    using (XML Spy and xmllint) all validate the sample document and do not
    pick up that the name is not unique.
    Any clues as to what could be going wrong?

    Thanks.

    -----------------------------------------------------------------------------------------------------------------------------
    function_list.xsd:
    <?xml version="1.0" encoding="UTF-8"?>
    <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    elementFormDefault="qualified" attributeFormDefault="unqualified">
    <xs:element name="function_list">
    <xs:complexType>
    <xs:sequence maxOccurs="unbounded">
    <xs:element ref="function"/>
    </xs:sequence>
    </xs:complexType>
    <xs:unique name="unique_fn_name">
    <xs:selector xpath="function_list"/>
    <xs:field xpath="@name"/>
    </xs:unique>
    </xs:element>
    <xs:element name="function">
    <xs:complexType>
    <xs:attribute name="name" type="xs:string" use="required"/>
    <!-- want the above attribute to be unique -->
    </xs:complexType>
    </xs:element>
    </xs:schema>

    -----------------------------------------------------------------------------------------------------------------------------
    function_list.xml:

    <?xml version="1.0" encoding="UTF-8"?>
    <function_list xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:noNamespaceSchemaLocation="function_list.xsd">
    <function name="fred"/>
    <function name="fred"/>
    <function name="frog"/>
    <function name="fred"/>
    </function_list>
     
    , Jul 26, 2006
    #1
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  2. George Bina Guest

    Hi,

    Your unique constrint does not select any nodes because you are in a
    function_list element and you select as selector all the cildren
    elements that have the name function_list and there are no such
    elements in your instance document

    <xs:selector xpath="function_list"/>

    What you want is probably

    <xs:selector xpath="function"/>

    Best Regards,
    George
    ---------------------------------------------------------------------
    George Cristian Bina
    <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
    http://www.oxygenxml.com

    wrote:
    > Hi All,
    >
    > In the sample schema & document below, I'd like the attribute "name" to
    > be unique for all function elements under function_list. The tools I'm
    > using (XML Spy and xmllint) all validate the sample document and do not
    > pick up that the name is not unique.
    > Any clues as to what could be going wrong?
    >
    > Thanks.
    >
    > -----------------------------------------------------------------------------------------------------------------------------
    > function_list.xsd:
    > <?xml version="1.0" encoding="UTF-8"?>
    > <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    > elementFormDefault="qualified" attributeFormDefault="unqualified">
    > <xs:element name="function_list">
    > <xs:complexType>
    > <xs:sequence maxOccurs="unbounded">
    > <xs:element ref="function"/>
    > </xs:sequence>
    > </xs:complexType>
    > <xs:unique name="unique_fn_name">
    > <xs:selector xpath="function_list"/>
    > <xs:field xpath="@name"/>
    > </xs:unique>
    > </xs:element>
    > <xs:element name="function">
    > <xs:complexType>
    > <xs:attribute name="name" type="xs:string" use="required"/>
    > <!-- want the above attribute to be unique -->
    > </xs:complexType>
    > </xs:element>
    > </xs:schema>
    >
    > -----------------------------------------------------------------------------------------------------------------------------
    > function_list.xml:
    >
    > <?xml version="1.0" encoding="UTF-8"?>
    > <function_list xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    > xsi:noNamespaceSchemaLocation="function_list.xsd">
    > <function name="fred"/>
    > <function name="fred"/>
    > <function name="frog"/>
    > <function name="fred"/>
    > </function_list>
     
    George Bina, Jul 27, 2006
    #2
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  3. Guest

    Thanks George,

    Your advice worked :)
    The other thing that was tripping me up is that my real world example
    (as opposed to the canonical example I posted here) was using a default
    namespace, so I had to some further tweaking to get the xpath expr. to
    work correctly.


    George Bina wrote:
    > Hi,
    >
    > Your unique constrint does not select any nodes because you are in a
    > function_list element and you select as selector all the cildren
    > elements that have the name function_list and there are no such
    > elements in your instance document
    >
    > <xs:selector xpath="function_list"/>
    >
    > What you want is probably
    >
    > <xs:selector xpath="function"/>
    >
    > Best Regards,
    > George
    > ---------------------------------------------------------------------
    > George Cristian Bina
    > <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
    > http://www.oxygenxml.com
    >
    > wrote:
    > > Hi All,
    > >
    > > In the sample schema & document below, I'd like the attribute "name" to
    > > be unique for all function elements under function_list. The tools I'm
    > > using (XML Spy and xmllint) all validate the sample document and do not
    > > pick up that the name is not unique.
    > > Any clues as to what could be going wrong?
    > >
    > > Thanks.
    > >
    > > -----------------------------------------------------------------------------------------------------------------------------
    > > function_list.xsd:
    > > <?xml version="1.0" encoding="UTF-8"?>
    > > <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    > > elementFormDefault="qualified" attributeFormDefault="unqualified">
    > > <xs:element name="function_list">
    > > <xs:complexType>
    > > <xs:sequence maxOccurs="unbounded">
    > > <xs:element ref="function"/>
    > > </xs:sequence>
    > > </xs:complexType>
    > > <xs:unique name="unique_fn_name">
    > > <xs:selector xpath="function_list"/>
    > > <xs:field xpath="@name"/>
    > > </xs:unique>
    > > </xs:element>
    > > <xs:element name="function">
    > > <xs:complexType>
    > > <xs:attribute name="name" type="xs:string" use="required"/>
    > > <!-- want the above attribute to be unique -->
    > > </xs:complexType>
    > > </xs:element>
    > > </xs:schema>
    > >
    > > -----------------------------------------------------------------------------------------------------------------------------
    > > function_list.xml:
    > >
    > > <?xml version="1.0" encoding="UTF-8"?>
    > > <function_list xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    > > xsi:noNamespaceSchemaLocation="function_list.xsd">
    > > <function name="fred"/>
    > > <function name="fred"/>
    > > <function name="frog"/>
    > > <function name="fred"/>
    > > </function_list>
     
    , Jul 27, 2006
    #3
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