RE: [xml-dev] Schema compile/validate problems in .NET 2.0

["Michael Kay" <mike@saxonica.com>]

This set of schemas is almost certainly making assumptions about the behaviour of constructs that are deliberately or unintentionally underspecified in the Schema Rec, and where differences of behaviour between different processors are therefore legitimate.

 

Duplicate definitions: the spec explicitly says that it doesn't define how component identity is established, which means that whenever you include the same schema document into two other documents you run the risk that some processor is going to reject components as duplicates.

 

xs:redefine: this is a minefield for compatibility problems because the spec leaves so many cases undefined, for example circular redefines, two schema documents both redefining a third (in compatible or incompatible ways), and so on. If you want portability, xs:redefine is best avoided.

 

Hopefully we'll do something about this in XML Schema 1.1 - if you can identify more specifically the cause of the incompatibilities, this will help. In the meantime there's not much you can do other than testing under a variety of popular processors and tweaking the code until it works.

 

Michael Kay

http://www.saxonica.com/

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From: Marshall, Steven (SKM) [mailto:SMarshall@skm.com.au]
Sent: 05 February 2008 04:39
To: xml-dev@lists.xml.org
Subject: [xml-dev] Schema compile/validate problems in .NET 2.0

Hello,

 

We are developing an application which is based on a complex set of XML schemas (several dozen schemas in all).  The schemas themselves are based on the ISO19139 standard, with a few extensions and changes for our purposes.  Some of the changes are done using xs:redefine.  The set of schemas validates perfectly using oXygen version 8 and the Xerces engine.  The application is developed using Visual Studio on the .NET 2.0 platform.  The problem is, when I try to load the root schema into a .NET XMLSchemaSet object and call the Compile method, it throws about 16 validation exceptions.  Some describe duplicate definitions of elements or types, some complain about invalid xs:redefine usage.  It has thrown us a bit that oXygen does not report anything, but .NET will not accept these schemas.  Even if I try to load the unmodified ISO19139 schema set, .NET reports 3 errors which again, oXygen does not.

 

Anybody know what is going on here?  Is .NET more stringent in its validation than oXygen?  Even if we ask oXygen to use the MSXML.NET engine to validate them, we get different results.  It's difficult to post any of the schema info, because there is a total of well over a megabyte of it.  Initially we'd just like to know if anyone has come up against this sort of problem, and more important, has found a way through it.

 

Thanks and regards

Steve Marshall

 

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