Re: XSD 1.1 assert and id()

XSD 1.1 states Part 1, =A73.13.1):

To check an assertion, an instance of the XPath 2.0 data model ([XDM]) =
is constructed, in which the element information item being =B7assessed=B7=
 is the (parentless) root node

and XPath Functions and Operators states (=A715.5.2 fn:id):

If $node, or the context item if the second argument is omitted, is a =
node in a tree whose root is not a document node [err:FODC0001] is =
raised.

Taking these two statements together, using id() in an XSD assertion =
will always fail.

Michael Kay
Saxonica




On 18 Nov 2013, at 10:18, Maik St=FChrenberg =
<[email protected]> wrote:

> Hello,
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> I know that XSD 1.1 assert elements are restricted to descendent nodes =
of the content node that is asserted.
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> It seems to me, that this rule does prevent the use of the id() =
function, since it could be used to access nodes out of scope.
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> See the simple XSD below. I have a number of movies, a number of =
customers and rentals. Each movie has an age certificate and each =
customer has an age, both have an ID. Rentals should only be allowed if =
the customer's age is greater or equal the certificate.
> I've tested the XPath expression already with an XSLT 2.0 stylesheet =
and it worked with Saxon-EE, but the same Saxon-EE raises an error when =
used as a schema validator on the instance file below.
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> I just wanted to assure, that this behaviour is related to the =
'only-descendents-rule'.
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> Best,
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> Maik
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> <?xml version=3D"1.0"?>
> <xs:schema xmlns:xs=3D"http://www.w3.org/2001/XMLSchema">
>  <xs:element name=3D"movies">
>    <xs:complexType>
>      <xs:sequence>
>        <xs:element maxOccurs=3D"unbounded" name=3D"movie">
>          <xs:complexType>
>            <xs:sequence>
>              <xs:element name=3D"title" type=3D"xs:string"/>
>            </xs:sequence>
>            <xs:attribute name=3D"certificate">
>              <xs:simpleType>
>                <xs:restriction base=3D"xs:int">
>                  <xs:enumeration value=3D"6"/>
>                  <xs:enumeration value=3D"12"/>
>                  <xs:enumeration value=3D"16"/>
>                  <xs:enumeration value=3D"18"/>
>                </xs:restriction>
>              </xs:simpleType>
>            </xs:attribute>
>            <xs:attribute name=3D"no" use=3D"required">
>              <xs:simpleType>
>                <xs:restriction base=3D"xs:ID">
>                  <xs:pattern value=3D"F[0-9]{6}"/>
>                </xs:restriction>
>              </xs:simpleType>
>            </xs:attribute>
>          </xs:complexType>
>        </xs:element>
>        <xs:element name=3D"customer">
>          <xs:complexType>
>            <xs:sequence>
>              <xs:element name=3D"name" type=3D"xs:string"/>
>            </xs:sequence>
>            <xs:attribute name=3D"no" use=3D"required">
>              <xs:simpleType>
>                <xs:restriction base=3D"xs:ID">
>                  <xs:pattern value=3D"K[0-9]{6}"/>
>                </xs:restriction>
>              </xs:simpleType>
>            </xs:attribute>
>            <xs:attribute name=3D"age">
>              <xs:simpleType>
>                <xs:restriction base=3D"xs:int">
>                  <xs:minInclusive value=3D"12"/>
>                  <xs:maxInclusive value=3D"110"/>
>                </xs:restriction>
>              </xs:simpleType>
>            </xs:attribute>
>          </xs:complexType>
>        </xs:element>
>        <xs:element name=3D"rentals">
>          <xs:complexType>
>            <xs:sequence maxOccurs=3D"unbounded">
>              <xs:element name=3D"rental">
>                <xs:complexType>
>                  <xs:sequence>
>                    <xs:element name=3D"customer">
>                      <xs:complexType>
>                        <xs:attribute name=3D"no" type=3D"xs:IDREF" =
use=3D"required"/>
>                      </xs:complexType>
>                    </xs:element>
>                    <xs:element name=3D"movie" maxOccurs=3D"unbounded">
>                      <xs:complexType>
>                        <xs:attribute name=3D"no" type=3D"xs:IDREF" =
use=3D"required"/>
>                      </xs:complexType>
>                    </xs:element>
>                  </xs:sequence>
>                  <xs:assert
>                    test=3D"if (id(customer/@no)/@age ge =
id(movie/@no)/certificate) then (true()) else false()"/>
>                </xs:complexType>
>              </xs:element>
>            </xs:sequence>
>          </xs:complexType>
>        </xs:element>
>      </xs:sequence>
>    </xs:complexType>
>  </xs:element>
> </xs:schema>
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> <movies xmlns:xsi=3D"http://www.w3.org/2001/XMLSchema-instance"
> xsi:noNamespaceSchemaLocation=3D"movie-minimal.xsd">
>  <movie certificate=3D"12" no=3D"F123456">
>    <title>Star Wars</title>
>  </movie>
>  <customer no=3D"K999999" age=3D"14">
>    <name>Max</name>
>  </customer>
>  <rentals>
>    <rental>
>      <customer no=3D"K999999"/>
>      <movie no=3D"F123456"/>
>    </rental>
>  </rentals>
> </movies>
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> --=20
> Dr. Maik St=FChrenberg
> Universit=E4t Bielefeld
> Fakult=E4t f=FCr Linguistik und Literaturwissenschaft
> Universit=E4tsstra=DFe 25
> 33615 Bielefeld
> Telefon: +49 (0)521/106-2534
> E-Mail: [email protected]
> http://www.maik-stuehrenberg.de
> http://www.xstandoff.net
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