i need rdf views .i have used d2r server and generate .n3 file.is that .n3 file is rdf view ?
asked 15 Jan '13, 10:38
Well, maybe. Some people use the word "view" to implicitly mean a non-materialized view. If that's what you mean then "no, it isn't." :-)
answered 15 Jan '13, 14:52
No, the *.n3 file is not exactly a view. It is a mapping file to generate the triples.
It is written in a D2RQ Mapping Language, described here.
The D2R Server produces the triples as it needs them. So if you make a Query "A", then modify the database and ask again about "A" you might recover different values. "A" was making use of one table that was updated. This works because you define a transformation between Rows to RDF triples (in the simplest case); I mean, you map the structure, not the data itself.
The term view has sense in Virtuoso, where the relational mapping language is named as Data Views.
All these systems don't generate a RDF dump, neither make use of it afterwards. They generate the triples when they need them.
PD: Other option for mapping and Query Relational data as SPARQL would be Spyder. With the advantage that Spyder uses R2RML, W3C recommended language for mappings.