Redefining Old Datatypes

XSD Tutorials - Herong's Tutorial Examples

∟Linking Multiple Schema Documents Together

∟Redefining Old Datatypes - Errors

This section describes a tutorial example of incorrect usages of 'redefine' components on changing existing datatypes.

One common error on using "redefine" components is that the redefined datatype uses a name different than the base datatype. Here is a sample schema document, address_redefine_error.xsd, that has this type of errors:

<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
 <xsd:annotation>
  <xsd:documentation>address_redefine_error.xsd
 - Copyright (c) 2002-2013 HerongYang.com. All Rights Reserved.
  </xsd:documentation>
 </xsd:annotation>

 <xsd:redefine schemaLocation="address_us.xsd">
  <xsd:annotation>
   <xsd:documentation>
    Modifying the "addressUsType" definition
   </xsd:documentation>
  </xsd:annotation>

  <xsd:complexType name="addressOverseaType">
   <xsd:complexContent>
    <xsd:extension base="addressUsType">
     <xsd:sequence>
      <xsd:element name="country" type="xsd:string"/>
     </xsd:sequence>
    </xsd:extension>
   </xsd:complexContent>
  </xsd:complexType>
 </xsd:redefine>

  <xsd:element name="addressOversea" type="addressOverseaType"/>

</xsd:schema>

Here is the error message reported by the schema checker program, XsdSchemaChecker.java:

herong> java XsdSchemaChecker address_redefine_error.xsd

Error:
   Line number: 18
   Column number: 41
   Message: src-redefine.5.b.d: 'extension' does not have a 'base'
   attribute that refers to the redefined element,
   ',addressOverseaType'. <complexType> children of <redefine>
   elements must have <extension> or <restriction> descendants,
   with 'base' attributes that refer to themselves.

Failed with 1 errors.