Redefining Old Datatypes - Errors

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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) 2007 by Dr. Herong Yang. 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:

>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.

Sections in This Chapter

Schema Component Reuse - "include", "redefine" or "import"

Including Old Schema Documents - "include" Component

Including Old Schema Documents - Examples

Including Old Schema Documents - Errors

Redefining Old Datatypes - "redefine" Component

Redefining Old Datatypes - XML Examples

Redefining Old Datatypes - Errors

Importing Declarations Across Namespaces - "import" Component

Importing Declarations Across Namespaces - Examples

Using Elements Declared in Different Namespaces

Using Elements Declared in Different Namespaces - Errors