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Re: RDF in OO-databases

From: Dan Brickley <Daniel.Brickley@bristol.ac.uk>
Date: Sat, 8 Jan 2000 11:05:01 +0000 (GMT)
To: heiko.grussbach@crpht.lu
cc: www-rdf-interest@w3.org
Message-ID: <Pine.GHP.4.21.0001081050010.13996-100000@mail.ilrt.bris.ac.uk>
On Fri, 7 Jan 2000 heiko.grussbach@crpht.lu wrote:

> Hi,
> 
> I remember a few months ago, there was a discussion on how to store RDF in
> relational databases. Does anybody have experience or ideas on how to store
> RDF in object-relational or pure object-oriented databases?

I don't have a general answer, but you might find the Ozone database
worth a look. I've just (like, as I type) started to play with this as a
possible way of persisting RDF objects. It's pure Java, Open Source and
has well documented installation instructions. Beyond that I'll let you
know how my experiments go when I've actually done something with my new
installation...

Ozone is of the 'persistant java classes' school of OO
databasery; ie. there is no query language so we don't get to look at
issues of mapping RDF query to object database queries. 

	(excerpt from docs)
	A second point is the integration of ozone in Java. There is
	no special query language and no interface definition
	language. The database scheme is generated from the Java
	byte code. All queries are simple Java methods. Database
	classes are derived from a ozone class or support a specific
	interface. Beyond that the programming of database
	classes doesn't differ from the programming of normal
	classes. 

Given an in-memory RDF graph, this would give one way of stashing it on
disk OOdb style. The Ozone site contains more information on 'ozoneXML' where
they've done exactly this for the XML DOM API. Naively, I'm thinking
that if it works for DOM it should work for RDF apps too. Performance
would be another matter though. The site claims that their DOM
implementation "gives us the possibility to do highly
optimized queries on plain DOM structures.". If anyone has more
experiment of Ozone and ozoneXML in practice, do tell...

Ozone is at http://www.ozone-db.org/


Dan
Received on Saturday, 8 January 2000 06:06:09 GMT

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