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Re: RDF vs. relational databases

From: Henry Story <henry.story@bblfish.net>
Date: Tue, 29 Aug 2006 16:37:39 +0200
Message-Id: <41B97055-A5DC-48E0-B2A3-EB5E799761E4@bblfish.net>
Cc: "revi s." <reviswami78@yahoo.com>, www-rdf-interest@w3.org
To: Maciej Gawinecki <mg@bydnet.pl>

On 29 Aug 2006, at 16:29, Maciej Gawinecki wrote:
> Also, as usual the question is what for are you going to use it.  
> Relational databases will win in performance competition, when you  
> are talking about processing flat-structured data with linear order  
> and it is often worth of consideration whether use of RDF e.g. for  
> data-minining.

I think relational databases may win in performance competitions now,  
but not in the future when Just In Time RDF databases come out. Just  
as with Java people argued that it necessarily had to be slower since  
the byte code had to be interpreted, but now Java is often faster  
than C. Java can be faster than C, because it can optimize the  
compilation by looking at how the code is *used*. Since RDF is much  
easier to refactor, I can imagine exactly the same situation applying  
there too. The database could look to find what queries get asked  
more often and re-allign it's internal structure to match.

Just a thought.

> On the opposite site there are RDF graphs where travelling from one  
> node to another one is usually more time-consuming but let's you  
> express relations with starting node clearly.
> There are some solutions where people store RDF graphs in  
> persistent database models (by translating RDF graph into relations  
> inside of db tables), and there are some encouraging results with  
> performance. See topic of persistent models at:
> http://jena.sourceforge.net
> for more,
> Regards,
> Maciej
> Henry Story napisaƂ(a):
>> This is how I would put it in short:
>> "The Semantic Web is to all previous data formats what the  
>> internet is to the previous networking protocols. It abstracts,  
>> interconnects and overlays them. It can do this because it uses  
>> URIs at its core."
>> As soon as you want to be able to use data in a network  
>> environment, rdf is your friend. On the other hand the older  
>> technologies have been around for longer, so they are better  
>> understood, and much better tooled.
>> Henry
>> On 29 Aug 2006, at 03:14, revi s. wrote:
>>> I'm a newbie to RDF and have been facing a fundamental question  
>>> as read
>>> more about RDF. RDF positions itself away from plain XML
>>> representations of data saying XML suited for representing data with
>>> containment hierarchies, and where "order" is important, whereas RDF
>>> has a flatter structure, represents only references among different
>>> entities. That sounds just like what a relational database is  
>>> supposed
>>> to do, and those are critieria when deciding whether to used an  
>>> XML DB
>>> or a relational DB to store your data.
>>> Where does RDF fit in, and how does it compare to relational  
>>> databases.
>>> I keep hearing that databases are not good for "semi-structured"  
>>> data,
>>> but am not yet able to understand how RDF addresses that. Mozilla  
>>> for
>>> example uses RDF for very structured (table of content) data.
>>> What would be points of comparison where RDF is better suited to  
>>> store
>>> and query my data?
>>> Revi S.
>>> Stay in the know. Pulse on the new Yahoo.com. Check it out.
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Received on Tuesday, 29 August 2006 14:38:04 UTC

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