Declaring Complex Elements with Attributes and Sub Elements

XSD Tutorials - Herong's Tutorial Examples

∟Declaring Complex Elements with Attributes and Sub Elements

This section describes a tutorial example on how to declare an element that accepts attributes and sub (child) elements without text content using a user defined complexType datatype.

A complex element with sub elements and attributes only is an element with sub (child) elements and attributes, but no text content. This type of element can be declared with a "complexType" datatype with "complexContent" containing some "element"s and some "attribute"s.

A good example of complex elements with attributes only is the <table> element in HTML documents. It accepts only attributes like "border" and sub elements like <tr>. But it should not have any text content.

Combine the rules described in the previous two tutorials, we should be able to define a complex element with sub elements and attributes only by putting the "sequence" of "element" and "attribute" inside "restriction".

Rule 1. The "sequence" of "element" component must be placed before and "attribute" component, if both of them are included in "restriction".

Here is a sample schema, complexType_no_text_content.xsd, that defines <table> to accept sub elements and attributes only, and no text content:

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

 <xs:element name="table">
 <xs:complexType>
  <xs:complexContent>
   <xs:restriction base="xs:anyType">
    <xs:sequence>
    <xs:element name="tr" type="xs:anyType" maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:attribute name="border" type="xs:string"/>
   </xs:restriction>
  </xs:complexContent>
 </xs:complexType>
 </xs:element>

</xs:schema>

Let's try this schema on a sample XML document, complexType_no_text_content.xml, with some errors:

herong> type complexType_no_text_content.xml

<?xml version="1.0"?>
<table border="1" note="Tutorials">
 <tr><td>Left</td><td>Right</td></tr>
 <tr><td>Apple</td><td>Orange</td></tr>
 Example
</table>


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

Error:
   Line number: 2
   Column number: 36
   Message: cvc-complex-type.3.2.2: Attribute 'note' is not allowed
   to appear in element 'table'.

Error:
   Line number: 6
   Column number: 9
   Message: cvc-complex-type.2.3: Element 'table' cannot have
   character [children], because the type's content type is
   element-only.

Failed with errors: 2