Hello, > Note also that you should not be reasoning directly over a TDB model. > The inference engines available in Jena are all memory based so there's > no scaling advantage, and a large performance hit, to reasoning directly > over TDB/SDB. Instead load your data into a memory model and reason over > that.
OK, thanks i will try to re-model my program in a way that it reasons on the memory model only. Let's see if this will result in a performance increase. > Sure. There's no requirement that a given ontology only mention URIs > which correspond to its default namespace. A single OWL or RDF graph can > contain data crossing many namespaces quite freely. > > I'm confused about whether you are being given ontologies which talk > about different individuals which you want to merge or whether you are > in fact generating these partitioned ontologies yourself just for > management/performance reasons. you could say I am given ontologies which talk about different classes that i want to merge. The member individuals of these classes are however created by me, and in future by my implementation, and could be created with the namespace of either of the two ontologies, or in one ontology which is the result of the union of the two ontologies. > My interpretation was that you had two ontologies which talk about the > same concept but using different URIs and you wanted to map those > concepts together so you could query the resulting union. I would do > that by constructing the union (not intersection) as a separate third > model. There is then a choice of how to represent the mapped concepts in > the merged model. Among the options are: > (a) Pick one the source URIs as definitive, use that in the merged > model, map statements about the other alias URI as you do the merge. > (b) Create a new URI for the merged concept and map statements about > both the source URIs to the new merged concept. > (c) Keep both source URIs in the merged model and use owl:sameAs > assertions to represent the mapping. Thank you again, I will try the options that you suggested. However, at the moment with the equipment that i have available and the size/complexity of my ontologies a direct import (owl:import) with necessary assertions (e.g.owl:equivalentClass, owl:sameAs) always resulted in an unacceptable reasoning performance. Best Regards, Mario
