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TripleLite

TripleLite

TripleLite is an in-memory RDF triple store for Python, optimized for speed and memory efficiency. The storage engine is written in C, with a Python API on top. It supports configurable reverse indexing per predicate.

Install

Section titled “Install”
Terminal window
pip install triplelite

Need rdflib interop? Install the extra:

Terminal window
pip install triplelite[rdflib]

Quick start

Section titled “Quick start”

This example models the article “OpenCitations, an infrastructure organization for open scholarship” using predicates from the OpenCitations Data Model:

from triplelite import TripleLite, RDFTerm


DCTERMS = "http://purl.org/dc/terms/"
FABIO = "http://purl.org/spar/fabio/"
FRBR = "http://purl.org/vocab/frbr/core#"
PRISM = "http://prismstandard.org/namespaces/basic/2.0/"
XSD = "http://www.w3.org/2001/XMLSchema#"
RDF_TYPE = "http://www.w3.org/1999/02/22-rdf-syntax-ns#type"


OC = "https://w3id.org/oc/meta/"
article = f"{OC}br/062501777134"
journal = f"{OC}br/062501778099"


g = TripleLite(identifier=f"{OC}br/")


g.add_many([
    (article, RDF_TYPE, RDFTerm("uri", f"{FABIO}JournalArticle")),
    (article, f"{DCTERMS}title",
     RDFTerm("literal", "OpenCitations, An Infrastructure Organization For Open Scholarship")),
    (article, f"{PRISM}publicationDate",
     RDFTerm("literal", "2020-02", f"{XSD}gYearMonth")),
    (article, f"{PRISM}volume", RDFTerm("literal", "1")),
    (article, f"{PRISM}startingPage", RDFTerm("literal", "428")),
    (article, f"{PRISM}endingPage", RDFTerm("literal", "444")),
    (article, f"{FRBR}partOf", RDFTerm("uri", journal)),
])

Query by pattern (None is a wildcard):

for s, p, o in g.triples((article, None, None)):
    print(p.split("/")[-1], "->", o.value)


for obj in g.objects(article, f"{DCTERMS}title"):
    print(obj.value)


print(len(g))  # 7

Remove by pattern:

g.remove((article, f"{PRISM}startingPage", None))
g.remove((article, f"{PRISM}endingPage", None))
print(len(g))  # 5

Single add vs batch add

Section titled “Single add vs batch add”

add() inserts one triple. add_many() accepts any iterable and avoids per-call overhead by caching internal lookups across the batch. Use add_many() when loading data from a file, a SPARQL result set, or any source with more than a handful of triples:

g.add((article, f"{DCTERMS}title", RDFTerm("literal", "Some title")))


g.add_many(
    (str(s), str(p), RDFTerm("uri", str(o)))
    for s, p, o in some_external_source
)

Both methods deduplicate: adding a triple that already exists is a no-op.

What’s next

Section titled “What’s next”