Hi,

Is there a way to specify a CDATASection within XSD? I know my element content is going to contain values that need not to be parsed within my XML document, so want to ensure that the relevant elements contain CDATA sections.

cheers

Chris




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Chris

Think of CDATA simply as an alternative way of escaping special characters. Writing <A><![CDATA[<&>]]></A> is exactly equivalent to writing <A>&lt;&amp;&gt;</A>. If there aren't any special characters, then CDATA is completely redundant: <A><![CDATA[ABC]]></A> is just a long-winded way of writing <A>ABC</A>. The receiving application should process both in exactly the same way, and so it shouldn't care which was used on input. The purpose of the schema is to control the logical structure of the document, not the choice of escaping conventions for character data.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

> The purpose of the schema is to control the
> logical structure of the document, not the choice
> of escaping conventions for character data.

Cool. Now look at it from a developer's point of view.

(1) Define XSD
(2) Generate classes using a 3rd party tool
(3) Convert class information to XML at runtime via a standard translator like XmlSerializer

See a problem? Without a way to tell the XSD that "this field here needs to be escaped," you are right back into hand-coding one portion or another of the pipeline.

If the XSD committee doesn't want to dirty its hands with CDATASection, it at least should provide a way to say "this field needs to be escaped." Which in the real world means the thing will be CDATA....

So the real answer to the original post is, "Sorry buddy, you're screwed because there is no way to do this with XSD."

Jim

A serializer must apply escaping to all text nodes (either using &amp; and &lt; or using CDATA) unless it knows that they can't contain &, <, or ]]>.

It's probably just as easy for the serializer to look at the actual content of the text or attribute node to see whether it contains special characters as to look in the schema.



Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

<xsd:element name="description" type="xsd:string" sql:field="description" sql:use-cdata="1"/>