[gnome-db] Re: gda-report-document

[idstewart softhome net]

Santi Camps writes: 

> El sáb, 02-11-2002 a las 14:46, idstewart softhome net escribió:
> > Gonzalo Paniagua Javier writes:  
> >
> > > * [ Santi Camps <santicamps wanadoo es>
> > > * Wed, 30 Oct 2002 18:29:08 +0100 ]
> > >> I'm not familiarized with XML Schema, I think that they are an
> > >> evolution of DTD, but that's all I know.  If this is true, it could be
> > >> better use XML Schema.
> > > 
> > > http://www.w3.org/TR/xmlschema-1/ and -2 
> > > 
> > > Yes, they are an evolution of DTDs, extending them to allow, not only
> > > defining entities, but their validation criteria and also data types. 
> >
> > We use XSD at work.  In addition to supporting fine grained validation 
> > criteria, it also supports extension- and restriction based subclassing.  
> >
> > One of the nicest aspects of this is, because XSD is itself rendered in XML, 
> > you can use XSD to extend XSD...  
>
> It seems that XML Schema is not completely implemented in libxml2, as
> Dmitry has wrote in a previous e-mail.   
>
> Do you use any other free library to do this?  Perhaps a non-free
> library?  A high level product?

Most of the work we do is in support of Enterprise System Management.  As 
such, we don't interact directly with the low-level libraries.  Rather, we 
use XML and XSD primarily for data definition purposes.  There are plans in 
the works to implement a SOAP interface, to allow Perl/mod_perl to interact 
with our J2EE middleware, and we will use XSD in conjunction with WSDL to 
facilitate that, but we aren't there just yet...

> > > 
> > > As i said in my previous mail, if libxml2 supports schemas, it would
> > > allow as to save some coding to validate data. 
> > > 
> > > But, well, if not, we can just use a DTD and validate the data by
> > > ourselves :-) 
> >
> > Why not use XSD and provide your own validation?  At the very least, parsing 
> > would be alot less painful.  
>
> I'm not sure what you are proposing.  Our intention is not implement any
> parsing, just use libxml to do it.  We are also thinking to use libxml
> to make some validations, but nowadays it seems that should be done
> using DTDs.

Yes, I read that message.  But it seems to me, if you are already 
contemplating developing your own DTD-based validation code (or did I 
misread that?), it would be little extra effort, and a lot more productive, 
to go ahead and make the switch to XSD. 

I'm not entirely certain why libxml2 doesn't support XSD-based validation, 
as it has been in production use for at least the last two years ('it' 
referring to XSD), but I suppose that is another matter entirely. 

> If you know another way that can be used from a free C library, could
> you explain it, please ?

Hmm...most of the work I do is with Perl and Java, but something to look 
into...I'll let you know if I uncover anything worthwhile. 


Ian