RE: XML

I asked a question along these lines on the Zaurus developer boards
(Spencer what has happened to zaurus.com!! It has been undergoing
maintenance all weekend) recently. While many peoples apps are using XML
they appear to be rolling their own XML parsers. I was asking for
suggestions on which of the many parsers out there would be best suited
to general use and as such could be made into an ipk for everyone to
use. There are a few libs already available in the debian arm archives.
The benefits are that we don't have to waste precious space on bundling
XML handlers each time.

I am not yet convinced that internal storage as XML is great but for
import and export it is ideally suited to many applications. However, if
the Z app imports data from a richer (more recent) DTD, it should not
discard those fields/data items that it does not understand simply
because they do not match its internal data structure. So how do others
deal with this? How do you selectively import, edit and export while
retaining unused data items in t heir proper context?! It is not
insurmountable of course but in the end I suspect it is just easier to
store the XML and compress the data file if it is likely to start to
consume anything above minimal space. A DOM parser is a damned site
easier to use in this context then farting around with SAX as well,
(memory concerns conveniently ignored >-))

Neil




Neil Horlock
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> -----Original Message-----
> From: [email protected] 
> [mailto:[email protected]] On Behalf 
> Of Tim Walker
> Sent: Monday, April 07, 2003 11:11
> To: [email protected]
> Cc: [email protected]
> Subject: Re: [Zaurus-devel] XML
> 
> 
> 
> Hmmn, yeah I've been playing with qconfig and the like, it's 
> a bit over the 
> top for what I'm trying to do, but usable.
> 
> Rik Hemsley suggested QDataStream which also has possibility...
> 
> I'm very much the perl/php + sql programmer and I get used to 
> having a simple 
> way of storing, accessing and searching data in an simply way.
> 
> select * from entries where date='20030505';
> 
> or whatever is rather easy to implement :)
> 
> I guess the biggest issue is that I was trying to avoid 
> having to create large 
> memory structures. For example if someone has 1000 entries in 
> this program, 
> than that 1000 instances of a class I have to 
> implement,sort,save to and read 
> from files blah blah. Which is going to chew ram. So 
> alternatively I can 
> leave it on disk and access each bit as I need, but then 
> we're talking disk 
> accesses for simple things like grabbing a list of every entry. 
> 
> If I'm willing to load a linked list or whatever into memory 
> at startup well 
> then QDataStream will probably be the most ecnomical way to go...
> 
> Tim
> 
> 
> 
> 
> On Mon, 7 Apr 2003 07:46 pm, you wrote:
> > Hi Tim,
> >
> > > I'm starting to suspect that xml support in the form of 
> QDomDocument 
> > > isn't
> > >
> > > compiled into qtopia-free.
> >
> > You are right, the QDom classes are not part of QtEmbedded.
> >
> > > What are people using the parse/write XML documents on 
> the Z? OR is 
> > > there any alternative classes for dumping data to file 
> easily rather 
> > > than have to write
> > > my own data file and parsers etc.
> >
> > for simple configuration data, use the Config class, that will 
> > read/write the ~/Settings/appname.conf file. It's no XML, 
> however. If 
> > you need XML, you have to port
> > some xml class yourself, I am afraid.
> >
> > Eggert
> 
> 
> 
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