What Is Simple Datatype?

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∟"simpleType" - Defining Your Own Simple Datatypes

∟What Is Simple Datatype?

This section describes simple datatypes. What is a simple datatype? How many built-in simple datatypes provided in XSD 1.1? Can I define my own simple datatypes?

What Is Simple Datatype? Simple Datatype is a datatype who's values are simple and have no XML structure. Simple datatypes can be used to declare:

XML Attributes.
XML Elements that have no attributes and no sub elements.

There are 2 sources of simple datatypes:

Built-in Simple Datatypes - XSD 1.1 offers 47 built-in simple datatypes, including "string", "decimal", "integer", "byte", "float", "date", "time", "hexBinary", etc..
User-defined Simple Datatypes - XSD 1.1 supports type definition components for you to define your own simple datatypes.

For example, the following XSD document uses a built-in simple datatype and a user-defined simple datatype to declare XML elements:

<?xml version="1.1"?>
<!-- simple_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="Simple_Datatype_Test">
  <xs:complexType>
    <xs:sequence>

      <!-- Using built-in simple datatype -->
      <xs:element name="Street" type="xs:string"
         maxOccurs="unbounded"/>

      <!-- Using user-defined simple datatype -->
      <xs:element name="ZIP" maxOccurs="unbounded">
        <xs:simpleType>
          <xs:restriction base="xs:token">
            <xs:pattern value="\d\d\d\d\d"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:element>

      </xs:sequence>
  </xs:complexType>
</xs:element>
</xs:schema>

Here is a sample XML document to test the above XSD document:

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

   <!-- Valid "Street" values -->
   <Street>500 Main Street</Street>

   <!-- Invalid "Street" values -->
   <Street>500 <b>Main</b> Street</Street>

   <!-- Valid "ZIP" values -->
   <ZIP>01210</ZIP>

   <!-- Invalid "ZIP" values -->
   <ZIP>01210<br/></ZIP>

</Simple_Datatype_Test>

When validating this XML document with my XsdSchemaValidator.java program presented earlier in the book, I get these errors:

herong> java XsdSchemaValidator
^^^ simple_datatype_test.xsd simple_datatype_test.xml

Error:
   Line number: 11
   Column number: 43
   Message: cvc-type.3.1.2: Element 'Street' is a simple type, so it
   must have no element information item [children].
   (Child element is not allowed)

Error:
   Line number: 17
   Column number: 25
   Message: cvc-type.3.1.2: Element 'ZIP' is a simple type, so it must
   have no element information item [children].
   (Child element is not allowed)

Error:
   Line number: 17
   Column number: 25
   Message: cvc-pattern-valid: Value '' is not facet-valid with
   respect to pattern '\d\d\d\d\d' for type
   '#AnonType_ZIPSimple_Datatype_Test'.

Error:
   Line number: 17
   Column number: 25
   Message: cvc-type.3.1.3: The value '' of element 'ZIP' is not
   valid.

Failed with errors: 4