Defining Complex Datatypes - "complexType" Element

This section describes a tutorial example on how to define a complex datatype to be used to declare an element that can accept attributes and/or sub elements.

If element is declared with a simple datatype, for example, the "string" built-in datatype, the element must be "simple" - not allowed to have any attributes and any sub (child) elements.

If you want to declare an element to accept attributes or sub elements, you need to use the Complex Type Definition Component.

Rule 1. The Complex Type Definition Component allows you to define a new complex datatype, which can be used to declare elements to accept attributes and/or sub (child) elements.

Rule 2. The XML representation of a Complex Type Definition Component is a "complexType" element.

Rule 3. A "complexType" must have "name" attribute, if it is used to define a named datatype.

Rule 4. A simple way to specify an attribute in a "complexType" is to add an "attribute" component.

Rule 5. A simple way to specify a list of sub elements is to add a "sequence" element component.

Here is an example schema document, term.xsd, that declares element "term" to accept two sub (child) elements and one attribute:

<?xml version="1.0"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<!-- term.xsd
 - Copyright (c) 2013, HerongYang.com, All Rights Reserved.
-->

 <!-- Using a complex datatype -->
 <xs:element name="term" type="termType"/>

 <!-- Defining "termType" -->
 <xs:complexType name="termType">
  <xs:sequence>
   <xs:element name="name" type="xs:string"/>
   <xs:element name="definition" type="xs:string"/>
  </xs:sequence>
  <xs:attribute name="update" type="xs:date"/>
 </xs:complexType>

</xs:schema>

The following XML document, term.xml, conforms to term.xsd:

<?xml version="1.0"?>
<term update="2007-01-01">
 <name>Extensible</name>
 <definition>Capable of being extended.</definition>
</term>

Last update: 2013.

Table of Contents

 About This Book

 Introduction to XML Schema

 XML Editor and Schema Processor - XMLPad

 Java API for XML Processing - JAXP

 JAXP - XML Schema (XSD) Validation

 Xerces2 Java Parser - Java API of XML Parsers

 Using Xerces2 Java API

XML Schema Language - Basics

 Schema and Schema XML Representation

 Checking Schema Documents - XsdSchemaChecker.java

 Creating Schema Documents - "schema" Element

 Declaring Root Elements - "element" Element

 Specifying Element Datatype - "type" Attribute

 Using XML Schema Built-in Datatypes

 Using XML Schema Built-in Datatypes Incorrectly

 Validating XML Documents against Schema Documents

 Deriving New Simple Datatypes - "simpleType" Element

Defining Complex Datatypes - "complexType" Element

 Validation Error Examples on Complex Datatypes

 Introduction of XSD Built-in Datatypes

 "string" and Its Derived Datatypes

 "decimal" and Its Derived Datatypes

 "dateTime" and Its Related Datatypes

 Miscellaneous Built-in Datatypes

 Facets, Constraining Facets and Restriction Datatypes

 "simpleType" - Defining Your Own Simple Datatypes

 Complex Element Declaration

 Identity-Constraints: unique, key and keyref

 Assertion as Custom Validation Rules

 XML Schema Location and Namespace in XML Documents

 Overriding Element Types in XML Documents

 Linking Multiple Schema Documents Together

 Glossary

 References

 PDF Printing Version