"NCName" Datatype Values and Representations

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∟"NCName" Datatype Values and Representations

This section describes the built-in datatype 'NCName' designed to support XML element and attribute names with no namespace prefix. 'NCName', stands for 'Non-Colonized Name', datatype is derived from 'Name' by removing ':' from the 'Name' value pattern.

If you look at string pattern used to define "Name" values, you will see colon ":" is allowed in "Name" values. This is needed to support XML element names that uses namespances like "xs:complexType".

In order to support "Name" values without ":", XSD provides another datatype called "NCName" stands for "Non-Colonized Name".

"NCName" is a datatype derived from the "Name" datatype by removing ":" from the "Name" value pattern.

Here is a sample XSD document that defines a sub element <NCName> to use "NCName" values:

<?xml version="1.1"?>
<!-- NCName_datatype_test.xsd
 - Copyright (c) 2002-2013 HerongYang.com. All Rights Reserved.
-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="NCName_Datatype_Test">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="NCName" type="xs:NCName"
        maxOccurs="unbounded"/>
    </xs:sequence>
  </xs:complexType>
</xs:element>
</xs:schema>

Here is a sample XML document that contains <NCName> elements to test that definition:

<?xml version="1.1"?>
<!-- NCName_datatype_test.xml
 - Copyright (c) 2002-2013 HerongYang.com. All Rights Reserved.
-->
<NCName_Datatype_Test>

<!-- 5 valid "NCName" elements -->
  <NCName>name_datatype_test</NCName>
  <NCName>complexType</NCName>
  <NCName>   w3.org  </NCName>
  <NCName>     head  </NCName>
  <NCName>   &#x5934;</NCName>

<!-- 5 invalid "NCName" elements -->
  <NCName>   xs:token</NCName>
  <NCName>complex Type</NCName>
  <NCName>      (html)</NCName>
  <NCName>    xs+token</NCName>
  <NCName>    1st_head</NCName>
</NCName_Datatype_Test>

Again, the JDK tool XsdSchemaValidator.java works nicely on this test. It reports 5 groups of errors for the last 5 invalid elements. But error messages do not provide the "NCName" string pattern