XSD Blog

3) Face it, although the idea of validating against a schema is nice and anal, the reality is that we end up with very large documents (partly simply because XML is verbose) which choke the tools we have available to us (or at least take a really long time to process, and require that you have scads of memory). So the distance between the fantasy and the reality is larger than it should be, and insufficiently acknowledged.
2) The XML parsers I've gotten my hands on all suck eggs when it comes to error messages. Well, the exception is the Oracle parser.
1) Are none of them happy with the W3C DTD for XML Schema? Is it because the parsers bite, or is it that the DTD bites? Who can tell? XML Spy doesn't barf on the DTD; I'm pretty much assuming it is just that all the parsers really do, in fact, bite. (I used the latest versions of the parsers as of like 8/25/00.)

My Source


<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xsd:schema PUBLIC "-//W3C//DTD XMLSCHEMA 19991216//EN" "http://www.w3.org/1999/XMLSchema.dtd" [
	<!ENTITY % p 'xsd:'>
	<!ENTITY % s ':xsd'>
]>

<xsd:schema xmlns:xsd="http://www.w3.org/1999/XMLSchema">

	<!-- (name, value) pair -->
	<xsd:element name="pair" >
		<xsd:complexType content="elementOnly">
			<xsd:element name="name" type="xsd:string"/>
			<xsd:element name="value" type="xsd:string"/>
		</xsd:complexType>
	</xsd:element>

</xsd:schema>

The Oracle Parser

Parsing file:///c:/dev/testsource/SchemaTest.xsd
http://www.w3.org/1999/part2.dtd: XML-0201: (Fatal Error) Expected name instead of %.
http://www.w3.org/1999/part2.dtd: XML-0192: (Fatal Error) Unexpected text in DTD.
Parser Exception: Expected name instead of %.

The Xerces-J Parser

String index out of range: 17
        at org.apache.xerces.framework.XMLParser.parse(XMLParser.java:878)
        at org.apache.xerces.framework.XMLParser.parse(XMLParser.java:900)
        at com.ibm.xml.parsers.NonValidatingDOMParser.parse(NonValidatingDOMParser.java:231)
        at com.auctia.util.DOMParser.xerces(DOMParser.java:48)
        at com.auctia.util.DOMParser.main(DOMParser.java:26)

The Microsoft Parser

Warning: Entity 'p' already defined, using the first definition.
Exception in thread "main" com.ms.xml.parser.ParseException: Missing entity 'xsdannotation'.
        at com.ms.xml.parser.Parser.error(Parser.java, Compiled Code)
        at com.ms.xml.parser.Parser.scanEntityRef(Parser.java)
        at com.ms.xml.parser.Parser.nextToken(Parser.java:120, Compiled Code)
        at com.ms.xml.parser.ContentModel.parseNode(ContentModel.java)
        at com.ms.xml.parser.ContentModel.parseList(ContentModel.java:120, Compiled Code)
        at com.ms.xml.parser.ContentModel.parseRootNode(ContentModel.java)
        at com.ms.xml.parser.ContentModel.parseModel(ContentModel.java:122, Compiled Code)
        at com.ms.xml.parser.ElementDecl.parseModel(ElementDecl.java:120, Compiled Code)
        at com.ms.xml.parser.Parser.parseElementDecl(Parser.java:119, Compiled Code)
        at com.ms.xml.parser.Parser.parseInternalSubset(Parser.java, Compiled Code)
        at com.ms.xml.parser.Parser.loadDTD(Parser.java)
        at com.ms.xml.parser.Parser.scanEntityRef(Parser.java)
        at com.ms.xml.parser.Parser.parseInternalSubset(Parser.java:120, Compiled Code)
        at com.ms.xml.parser.Parser.loadDTD(Parser.java)
        at com.ms.xml.parser.Parser.tryDocTypeDecl(Parser.java)
        at com.ms.xml.parser.Parser.parseProlog(Parser.java)
        at com.ms.xml.parser.Parser.parseDocument(Parser.java)
        at com.ms.xml.parser.Parser.safeParse(Parser.java)
        at com.ms.xml.parser.Parser.parse(Parser.java)
        at com.ms.xml.om.Document.load(Document.java)
        at com.ms.xml.om.Document.load(Document.java)
        at com.auctia.util.DOMParser.microsoft(DOMParser.java:35)
        at com.auctia.util.DOMParser.main(DOMParser.java:28)