Oxrdflib provides an rdflib store based on pyoxigraph.
This store is named "Oxigraph"
.
This store can be used as drop-in replacement of the rdflib default one. It support context but not formulas. Transaction support is not implemented yet.
SPARQL query evaluation is done by pyoxigraph instead of rdflib if the Oxigraph store is used. SPARQL update evaluation is still done using rdflib because of a limitation in rdflib context management.
Oxrdflib is available on Pypi and installable with:
pip install oxrdflib
The oxrdflib store is automatically registered as an rdflib store plugin by setuptools.
Warning: Oxigraph is not stable yet and its storage format might change in the future. To migrate to future version you might have to dump and load the store content. However, Oxigraph should be in a good enough shape to power most of use cases if you are not afraid of down time and data loss.
To create a rdflib graph using the Oxigraph store use
rdflib.Graph(store="Oxigraph")
instead of the usual
rdflib.Graph()
Similarly, to get a conjunctive graph, use
rdflib.ConjunctiveGraph(store="Oxigraph")
instead of the usual
rdflib.ConjunctiveGraph()
and to get a dataset, use
rdflib.Dataset(store="Oxigraph")
instead of the usual
rdflib.Dataset()
If you want to get the store data persisted on disk, use the open
method on the Graph
object (or ConjunctiveGraph
or Dataset
) with the directory where data should be persisted. For example:
graph = rdflib.Graph(store="Oxigraph", identifier="http://example.com") # without identifier, some blank node will be used
graph.open("test_dir")
The store is closed with the close()
method or automatically when Python garbage collector collects the store object.
If the open
method is not called Oxigraph will automatically use a ramdisk on Linux and a temporary file in the other operating systems.
To do anything else, use the usual rdflib python API.
It is also possible to directly inject a pyoxigraph Store
object directly into an Oxrdflib store:
graph = rdflib.Graph(store=oxrdflib.OxigraphStore(store=pyoxigraph.Store("test_dir")))
This might be handy to e.g. open the database as read-only:
graph = rdflib.Graph(store=oxrdflib.OxigraphStore(store=pyoxigraph.Store.read_only("test_dir")))
SPARQLStore
, Oxigraph joins the initBindings
parameter of the query
method after the query has been evaluated, instead of injecting them at the beginning of the query.Graph
bind
method are not persisted on disk but kept in memory. They should be added again each time the store is opened."OxSled"
and "OxMemory"
have been merged into the "Oxigraph"
store."OxSled"
has been dropped and replaced by a new storage system based on RocksDB.
To migrate you need to first dump your data in RDF using oxrdflib
0.2 and the serialize
method, then upgrade to oxrdflib
0.3, and finally reload the data using the parse
method.To run the test do first pip install -e .
to register the stores in rdflib plugin registry.
Then, cd tests && python -m unittest
should run the tests.
The code is automatically formatted using black. A pre-commit configuration is provided.
Run pip install pre-commit && pre-commit install
to install pre-commit as a git pre-commit hook in your clone.