[xsd-users] RE: Substitution groups & different namespaces.

[Moss, David R (SELEX Comms) (UK Christchurch)]

Boris,

I think I've misunderstood xsi:type - if I rewrite the instance document
using xsi:noNamespaceSchemaLocation as you suggest:

<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<b:UserDatabase xmlns:b="http://www.dave.com/Base"
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="http://www.dave.com/Base
test-users.xsd"
	
xsi:noNamespaceSchemaLocation="derived-user-config.xsd">

<b:TestUserConfig Number="12345">
   <Name>fred</Name>
</b:TestUserConfig>

<DerivedUserConfig Number="54321">
   <Name>bob</Name>
   <Age>50</Age>
</DerivedUserConfig>

</b:UserDatabase>


I can mix basic and derived user types and get validation as required.
Or am I missing something? :-)

Cheers,
Dave.

Dave Moss
SELEX Communications
Grange Road
Christchurch 
Dorset  BH23 4JE
United Kingdom
Tel: + 44 (0) 1202 404841
Email: david.r.moss at selex-comm.com


> -----Original Message-----
> From: Boris Kolpackov [mailto:boris at codesynthesis.com]
> Sent: 14 December 2006 08:51
> To: Moss, David R (SELEX Comms) (UK Christchurch)
> Cc: xsd-users at codesynthesis.com
> Subject: Re: Substitution groups & different namespaces.
> 
> Hi David,
> 
> Moss, David R (SELEX Comms) (UK Christchurch) <david.r.moss at selex-
> comm.com> writes:
> 
> > an exception is thrown stating:
> >
> > "There is no Grammar for uri: ."
> >
> > I'm thinking it has something to do with the derived xsi:type
specified
> > in the XML file being in a different (i.e. not in one at all)
namespace
> > to the Base types.
> 
> Here is what happens: (1) you have XML Schema validation enabled in
the
> underlying parser and (2) you specify a type in xsi:type attribute for
> which there is no schema can be found. Here are the number of ways in
> which you can address this:
> 
> 1. Specify the schema where the type is defined with, in your case,
the
>    xsi:noNamespaceSchemaLocation attribute:
> 
> <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
> <b:UserDatabase  xmlns:b="http://www.dave.com/Base"
>                  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>                  xsi:type="DerivedUserConfig_t"
>                  xsi:schemaLocation="http://www.dave.com/Base test-
> users.xsd"
>
xsi:noNamespaceSchemaLocation="derived-user-config.xsd">
> 
> </b:UserDatabase>
> 
> 
>   With this fix the parsing results in the following error, which
makes
>   sense:
> 
>   test-users.xml:7:60 error: Type 'DerivedUserConfig_t' that is used
in
>   xsi:type is not derived from the type of element 'UserDatabase'
> 
>   You can also use Xerces-C++ API for loading and caching schemas. Let
>   me know if you would like more pointers on this.
> 
> 
> 2. Disable validation in the underlying parser with the
>    xml_schema::flags::dont_validate flag:
> 
>    auto_ptr<Base::UserDatabase_t>
>      db( Base::UserDatabase( "test-users.xml",
>                              xml_schema::flags::dont_validate) );
> 
> 3. Use "lax" validation in the underlying parser. Lax validation means
>    that the instance will be validated only of the schema can be
found.
>    In your case that would mean that the XML instance will be
validated
>    while DerivedUserConfig_t won't. There is no XSD flag to request
lax
>    validation yet.
> 
> 
> hth,
> -boris

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