Mobile XML Databases and Synchronization

["Daniel Lanovaz" <daniel@tendara.com>]

We are looking for some feedback regarding usage
patterns and requirements for XML databases on
mobile devices (Palm, PocketPC, RIM, J2ME devices,
etc.), including mobile XML data synchronization
patterns and usage.

If you're using (or will be using) XML in a mobile
development project, we'd like to hear your
experiences and opinions -- the more opinionated, the
better.

We've also written a white paper entitled
"XML and Handhelds: Building Mobile Applications"
located at:

	http://www.tendara.com/pdf/XMLandHandheldsWhitepaper.pdf

The paper describes the utility of a mobile XML
database, XML synchronization and database
compression/encryption techniques. For example,
a 3MB XML text file is represented in 900K of
memory on the target device (compressed object
representation, full DOM traversal API, lazy
decompression of nodes as they are referenced, etc.).
We think of it as data stores from XML sources
"on the go." Using the XML engine on a PocketPC
(iPAQ) simply does not scale.

Any mobile war stories, usage patterns (including
synchronization needs), feedback or flames can be
directed here or to daniel@tendara.com.

Thank you in advance for your time.

Best Regards,
Daniel Lanovaz
daniel@tendara.com
http://www.tendara.com

======================= CUT HERE ====================
If you're not familiar with XML databases, one good
introduction is Ronald Bourret's summary located at:

	http://www.rpbourret.com/xml/XMLAndDatabases.htm

Or an article by David McGoveran:

	http://www.eaijournal.com/PDF/XMLMcGoveran.pdf

Issues of particular interest to us:

	+	Does your application require access to
		local data on a mobile device? If so,
		how much data needs to be stored locally?
		Would data access mostly involve reading,
		writing, or both reading and writing in
		equal portions?

	+	Are your mobile data storage needs best
		met by a mobile XML database or the
		alternatives (flat XML text files,
		relational databases, application-specific
		databases, etc.)?

	+	Do you need to synchronize changes to XML
		data between mobile devices and central
		data stores? In which direction?

	+	What types of application programming
		interfaces (APIs) to XML data would you
		find most useful on the mobile device?
		DOM and XPath? From which languages?
		JavaScript? VisualBasic? Java? C/C++?
		C#? Any .NET language?

	+	How important is data compression to
		your application? Would you find a
		mobile XML database capable of representing
		a 3MB XML file in 900K of memory, fully
		parsed and available through DOM and
		XPath APIs, helpful to your off-line
		applications?

	+	What mobile devices are you using?
		Pocket PC? Palm OS? RIM? Cell phones?

	+	Do you have any experiences or war
		stories that you'd like to relate regarding
		XML on mobile devices? Anything that you
		found particularly hard or problematic?

Best regards,
Daniel Lanovaz
daniel@tendara.com
http://www.tendara.com