Since quads (triple plus graph) are stored in a regular SQL table with special data types, changing the table layout to add a column is possible. This column would not however be visible to SPARQL without some extra tuning. For coarse grain provenance and security information, we recommend doing this at the graph level, where triples that belong together are tagged with the same provenance or security are in the same graph. The graph can then have the relevant metadata as its properties.

If tagging at the single triple level is needed, this will most often not be needed for all triples. Hence altering the table for all triples may not be the best choice. Making a special table that has the graph, subject, predicate and object of the tagged triple as a key and the tag data as a dependent part may be more efficient. Also, this table could be more easily accessed from SPARQL.

Using the RDF reification vocabulary is not recommended as a first choice but is possible without any alterations.

Alterations of this nature are possible but we recommend contacting us for specifics. We can provide consultancy on the best way to do this for each application. Altering the storage layout without some extra support from us is not recommended.