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Re: Repeating elements with fixed attribute values

From: Pete Cordell <petexmldev@tech-know-ware.com>
Date: Fri, 4 Jan 2008 15:24:58 -0000
Message-ID: <001001c84ee5$fba48680$a100a8c0@Codalogic>
To: "King, Jeffrey (Mission Systems)" <Jeff.King@ngc.com>, <xmlschema-dev@w3.org>

I'm afraid XSD doesn't allow you to do what you want.

You might be able to add schematron constraints to your XSD to allow you to 
specify what you want, but I'll have to leave that to others to explain. 
Other than that you are left with defining a schema that allows multiple 
'field' elements and then enforcing the additional constraints in your 
application.

FWIW XSD would allow you to define a schema that allowed instances of:

<root>
  <word name="one">
    <field>
        <field1><number1>any string here</number1></field1>
        <field2><number2>any string here</number2></field2>
        ...

but it sounds like you don't have that option.

HTH,

Pete Cordell
Codalogic
Visit http://www.codalogic.com/lmx/ for XML C++ data binding
----- Original Message ----- 
From: "King, Jeffrey (Mission Systems)" <Jeff.King@ngc.com>
To: <xmlschema-dev@w3.org>
Sent: Friday, January 04, 2008 2:29 PM
Subject: Repeating elements with fixed attribute values



I have an xml document similar to this:

<root>
  <word name="one">
    <field name="field1" number="1">any string here</field>
    <field name="field2" number="2">any string here</field>
    <field name="field3" number="3">any string here</field>
    ...
  </word>
  <word name="two">
    <field name="field4" number="4">any string here</field>
    <field name="field5" number="5">any string here</field>
    <field name="field6" number="6">any string here</field>
    ...
  </word>
</root>

The attributes have fixed values.  I am struggling to create a schema
for this.

If I take this approach:

<xs:schema attributeFormDefault="unqualified"
elementFormDefault="qualified"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="root">
    <xs:complexType>
      <xs:sequence>
        <xs:element maxOccurs="1" minOccurs="1" name="word">
           <xs:complexType>
             <xs:sequence>

             <xs:element maxOccurs="1" minOccurs="1" name="field">
               <xs:complexType>
                  <xs:simpleContent>
                     <xs:extension base="xs:string">
                       <xs:attribute name="name" type="xs:string"
use="required" fixed="field1" />
                       <xs:attribute name="number"
type="xs:unsignedShort" use="required" fixed="1" />
                     </xs:extension>
                 </xs:simpleContent>
              </xs:complexType>
             </xs:element>

<xs:element maxOccurs="1" minOccurs="1" name="field">
     <xs:complexType>
                    <xs:simpleContent>
                       <xs:extension base="xs:string">
                          <xs:attribute name="name" type="xs:string"
use="required" fixed="field2" />
                          <xs:attribute name="number"
type="xs:unsignedShort" use="required" fixed="2" />
                       </xs:extension>
       </xs:simpleContent>
                </xs:complexType>
              </xs:element>
            ...
          etc.

I get an error stating: "Elements with the same name and in the same
scope must have the same type".  I'm not sure what approach to take
here.  I think this is pretty elementary, but any help with finding a
solution would be appreciated.

Thank you.

Jeffrey
Received on Friday, 4 January 2008 15:25:35 GMT

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