Hi Marko, I think we're more or less on the same page here; it's clear that TP3 has a different API than TP2. If you look at the guts of TP3 GraphSail [1], it uses the modern APIs, and yet does adapt them to the Sail interface.
Something like PropertyGraphSail (or an equivalent Jena thing) still makes sense in TP3, as well. One interesting detail here is that in TP3, vertices can have labels, which can be turned into rdf:type statements (that, in turn, can be used to enable subclass/superclass inheritance if the graph is combined with a RDF schema. A TP3 equivalent of SailGraph would indeed be quite different in implementation -- strategies, not wrapper graph -- than what we had for Blueprints, and yet would serve the same purpose. Josh [1] https://github.com/joshsh/graphsail/tree/master/src/main/java/net/fortytwo/tpop/sail On Fri, Dec 15, 2017 at 10:22 AM, Marko Rodriguez <[email protected]> wrote: > Hello, > > The model proposed below is in-line with TinkerPop2’s way of thinking. > Unfortunately, TinkerPop3 and more so for TinkerPop4, the Graph “structure" > API will become deprecated. This means that the notion of “wrapping the > Graph API” has gone away for TP3 and will be completely gone in TP4. In > TP4, there will not even be a Graph API — no more Vertex, Edge, Property, > etc. Only the concept of a Graph with only methods like Graph.traversal(), > Graph.partitions(), etc. > > Why was this route taken? In TinkerPop3, there was a need to support any > language besides Java. This was why Gremlin bytecode and the concept of the > Gremlin traversal machine was introduced. A provider simply gets Gremlin > bytecode and has to do something with it. For the Java-based Gremlin > traversal machine, this is why providers implement their own GraphStep, > VertexStep, etc. For a Python-based Gremlin traversal machine, likewise… > > This means that SailGraph, GraphSail, PropertyGraphSail as stated below > don’t make sense in the current and future architectures. > > The next question becomes, "well how would you turn an RDF store into a > PropertyGraph?” Easy — implement your own custom GraphStep, VertexStep, > etc. and respective ProviderStrategies that will handle the bytecode > compilation accordingly. > > The next question becomes, “well how would a PropertyGraph support > reasoning?” Easy — implement your own custom DecorationStrategy that will > insert reasoning into the traversal giving the RDFS schema. For instance: > g.V().out(“likes”) > ==> > g.V().out(“knows”,”likes”) > iff “likes” is a sub-property of “knows” > > In essence, it is possible to do this integration of RDF and TinkerPop, it > just needs to be done at the correct level of abstraction so that it stays > in line with how TinkerPop is evolving, not how it was back in 2012. > > Take care, > Marko. > > http://markorodriguez <http://markorodriguez/>.com > > > On 2017-12-13 07:46, Joshua Shinavier <[email protected]> wrote: > > Hi Harsh,> > > > > Glad you are taking Daniel's work forward. In porting the code to the> > > TinkerPop code base, might I suggest we allow for not only > SPARQL-Gremlin,> > > but a whole suite of RDF tools as in TP2. Perhaps call the module> > > rdf-gremlin. Then we could have all of:> > > > > * SPARQL-Gremlin: executes standard SPARQL queries over a Property Graph> > > database> > > * GraphSail [1,2]: stores RDF quads in the database, explicitly, and> > > enables SPARQL and triple pattern queries over the quads> > > * PropertyGraphSail [3]: exposes a Property Graph with of two mappings > to> > > the RDF data model> > > * SailGraph [4]: takes an RDF triple store (not natively supporting> > > Gremlin) and enables Gremlin queries> > > * others? I have often thought that a continuous SPARQL implementation> > > built on Gremlin would be powerful> > > > > The biggest mismatch between the TP2 suite and what might be built for> > > Apache TinkerPop is that the previous suite was implemented using > (Eclipse)> > > RDF4j, whereas things seem to be leaning towards (Apache) Jena now.> > > However, the same principles could be applied.> > > > > Josh> > > > > > > [1] https://github.com/tinkerpop/blueprints/wiki/Sail-Ouplementation> > > [2] https://github.com/joshsh/graphsail> > > [3]> > > https://github.com/tinkerpop/blueprints/wiki/PropertyGraphSail- > Ouplementation> > > [4] https://github.com/tinkerpop/blueprints/wiki/Sail-Implementation > > http://markorodriguez.com > > > >
