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Re: XML schema - multiple import of module

• From: Lech Rzedzicki <xchaotic@gmail.com>
• To: "DUNN, Mark" <mark.dunn@oup.com>
• Date: Thu, 4 Jun 2009 18:03:26 +0100

The problem is bigger than you think, and quite honestly is more
conceptual that technical.
I would suggest separate schemas for main content and law extracts and
using NVDL for dispatching to a relevant schema.
In main.xsd allow for any elements from the 'law' namespace and it
should work fine.

In your case, I think the duplication occurs when you import both the
law and the struct into main as they both define title and p elements,
if you can avid that, you should be fine as well.

If you're still stuck with the problem, please contact me off-list and
I'll send you some samples of how I handled the exact same situation
in the past.

Lech

On Thu, Jun 4, 2009 at 5:35 PM, DUNN, Mark <mark.dunn@oup.com> wrote:
> Hello,
>
> I'm new to XML Schemas, and investigating conversion of a DTD to an XML
> Schema. I have a problem describing the Schema version of the following
> structure:
>
> <doc>
>  <div>
>  <title>Section 1</title>
>  <p>Some text...</p>
>  <p>
>   <law:extraxt>
>    <title>Title of Regulation</title>
>    <p>Text of regulation</p>
>   </law:extract>
>  </p>
>  </div>
> </doc>
>
>
> The problem is in the non-namespaced <title> and <p> elements occurring
> within the namespaced <law:extract> element. They are the same as the
> ones occurring outside this element, so I'd like to define them only
> once.
>
> My attempt at expressing this structure uses three .xsd files:
>
> main.xsd:
>
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
> xmlns="http://xsd.oup.com/ac-xsd/"
> xmlns:law="http://xsd.oup.com/ac-law/"
> targetNamespace="http://xsd.oup.com/ac-xsd/"
> elementFormDefault="qualified">
>        <xs:redefine schemaLocation="struct.xsd">
>                <xs:group name="paragraph-content">
>                        <xs:choice>
>                                <xs:group ref="paragraph-content"/>
>                                <xs:element ref="law:extract"/>
>                        </xs:choice>
>                </xs:group>
>        </xs:redefine>
>        <xs:import namespace="http://xsd.oup.com/ac-law/"
> schemaLocation="law.xsd"></xs:import>
>        ...
> </xs:schema>
>
> law.xsd:
>
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
> elementFormDefault="qualified"
> targetNamespace="http://xsd.oup.com/ac-law/"
> xmlns:law="http://xsd.oup.com/ac-law/"
> xmlns:struct="http://xsd.oup.com/ac-xsd/">
>        <xs:import schemaLocation="struct.xsd"
> namespace="http://xsd.oup.com/ac-xsd/"></xs:import>
>        <xs:element name="extract">
>                <xs:complexType>
>                        <xs:sequence>
>                                <xs:element ref="struct:title"
> minOccurs="0"/>
>                                <xs:element ref="struct:p"
> minOccurs="1"/>
>                        </xs:sequence>
>                </xs:complexType>
>        </xs:element>
>        ...
> </xs:schema>
>
>
> struct.xsd:
>
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
> elementFormDefault="qualified" attributeFormDefault="unqualified"
> targetNamespace="http://xsd.oup.com/ac-xsd/"
> xmlns="http://xsd.oup.com/ac-xsd/">
>        <xs:group name="general-inline">
>                <xs:choice>
>                        <xs:element ref="b"/>
>                        <xs:element ref="i"/>
>                </xs:choice>
>        </xs:group>
>        <xs:group name="paragraph-content">
>                <xs:choice>
>                        <xs:group ref="general-inline"></xs:group>
>                        <!-- ... [plus others] ... --->
>                </xs:choice>
>        </xs:group>
>        <xs:element name="p">
>                <xs:complexType mixed="true">
>                        <xs:choice minOccurs="0" maxOccurs="unbounded">
>                                <xs:group ref="paragraph-content"/>
>                        </xs:choice>
>                </xs:complexType>
>        </xs:element>
>        ...
> </xs:schema>
>
>
> When I try saving the schema files in XMLSpy 2009, I get an error saying
> that <title> is already declared, presumably because the file struct.xsd
> has ben imported twice.
>
> The W3C spec says that importing twice is legitimate, but vendors are
> encouraged to raise it as an error. Fair enough - I don't like the
> circularity in my description.
>
> But the structure itself seems reasonable, I just can't see a way of
> expressing it in XML Schema.
>
> Can anyone help?
>
>
> Kind regards,
>
> Mark Dunn
> XML Data Engineer
> Oxford University Press
>
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• References:
  • XML schema - multiple import of module
    • From: "DUNN, Mark" <mark.dunn@oup.com>