Thanks for the explanation.
Cheers
Pieter
On 21/12/2015 23:59, Joshua Shinavier wrote:
> Hi Pieter,
>
> Yes, it is possible to map RDF graphs, and also RDF datasets (collections
> of graphs with names), to a property graph data model without loss.
> GraphSail [1] had to do this in order to use Blueprints-based DBs as triple
> stores, querying over the RDF data and retrieving it. GraphSail uses a
> mapping almost identical to that of SailGraph [2] (see a schematic on that
> page), which maps RDF to property graphs. For the "opposite" of GraphSail
> and SailGraph (i.e. arbitrary property graphs to RDF), see
> PropertyGraphSail [3].
>
> Olaf Hartig discusses some incompatibilities between PG and RDF in his
> paper. Some essential things to keep in mind:
> *) In mapping between PG and RDF, you are forced to treat edges either as
> resources or as statements. If edges are statements, then any edge
> properties are lost in the PG-->RDF mapping (unless you were to do
> something a little weird with named graphs: one graph per statement). If
> edges are vertices, the RDF format is quite verbose and is not symmetrical
> with a useful RDF-->PG mapping. PropertyGraphSail supports two styles of
> mapping: one "verbose" (edge-reified) and the other compact (edges as
> statements).
> *) A straightforward RDF(datasets)-->PG mapping treats resources as
> vertices and statements as edges or as properties depending on the object,
> but this is more complicated if you want to preserve named graph metadata,
> as you can't attach metadata to PG properties. You already have a bit of a
> problem if you want to do anything graph-like with named graph metadata, as
> PG is not a hypergraph data model (no edges from edges).
>
> Best,
>
> Josh
>
>
> [1] https://github.com/tinkerpop/blueprints/wiki/Sail-Ouplementation
> [2] https://github.com/tinkerpop/blueprints/wiki/Sail-Implementation
> [3]
> https://github.com/tinkerpop/blueprints/wiki/PropertyGraphSail-Ouplementation
>
>
>
>
>
>
> On Mon, Dec 21, 2015 at 11:28 AM, pieter-gmail <[email protected]>
> wrote:
>
>> Thanks, I have just started on the rdf path.
>>
>> When you say the RDF data model and PG data model are not 100% aligned
>> does that mean that for some RDF models to PG model there will be
>> information loss or just a increase in complexity and efficiency?
>>
>> Does the same hold for the other way around PG model to RDF model?
>>
>> I'll have a look at your implementation to understand things better.
>>
>> Cheers
>> Pieter
>>
>> On 21/12/2015 18:46, Mike Personick wrote:
>>> The RDF data model and the PG data model are not 100% aligned. I know
>>> there have been a few academic papers on the subject. For Blazegraph I
>> am
>>> using a PG schema built on top of raw RDF. But a raw RDF graph would not
>>> work with the Blazegraph TP3 interface if it doesn't follow the PG
>> schema.
>>> On Mon, Dec 21, 2015 at 3:22 AM, pieter-gmail <[email protected]>
>>> wrote:
>>>
>>>> Found this recently, fyi
>>>>
>>>> http://arxiv.org/abs/1409.3288
>>>>
>>>> Cheers
>>>> Pieter
>>>>
>>>> On 12/12/2015 16:01, pieter wrote:
>>>>> Hi,
>>>>>
>>>>> I know many rdf vendors are TinkerPop providers.
>>>>>
>>>>> Can it work in the other direction, i.e. can a rdf dataset be loaded
>>>>> into a TinkerPop database?
>>>>> Is it possible to load any rdf dataset into TinkerPop without loss?
>>>>>
>>>>> Is this something TinkerPop is interested in?
>>>>>
>>>>> Thanks
>>>>> Pieter
>>>>>
>>>>>
>>
