Philip Howard, Research Director, Bloor Research, reports on the triple store feature in DB2 10.

In fact, the data in the triple store is not stored relationally but as an encoded vector, which is a different thing altogether. As the person who told me this was Curt Cotner, who is CTO for IBM Database Servers, I am inclined to believe him. I think the problem is that there are not enough people within IBM who actually appreciate and understand how important triple stores (otherwise known as graph or RDF databases) are going to be and haven’t felt the need to understand how they truly work …. It should be noted that DB2 is not a full graph database at this point as it lacks the inference engine that would generally be included in such environment, but it is likely that DB2 will be integrated with one of the open source engines of this type in due course.

Howard further notest that DB2 includes three data stores: relational, XML and triple store and questions whether it is valid to call it a RDBMS.

There’s an interesting sidebar to this triple store implementation as it means that DB2 now effectively has three different storage engines: relational, XML and triple store, each with its own access mechanism – SQL, XQuery and SPARQL. Now, if you’ve got three storage engines why not four or five? In fact, IBM is already working on a JSON store, accessible via SQL and with a callable interface like MongoDB. So, why not a Hadoop storage engine (HDFS or GPFS) as well? You’d get the low cost clustered hardware advantage, you’d get the advantage of “schema later” but you’d have a single management environment across multiple storage engines. Okay, don’t expect this tomorrow but I think this is the direction in which IBM is going to move: the addition of the triple store to DB2 is not only important in its own right I think it’s a pointer to the future. There is one outstanding question: if DB2 already has three distinct storage mechanisms and is likely to have more in the future then is it valid to continue to call it a relational database management system? Isn’t it a general-purpose database management system now or even just a data management system?
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