@metreeca/keep-sparql

SPARQL 1.1 repository connector for the @metreeca/keep model-driven linked data storage framework.

Translates @metreeca/keep storage operations into SPARQL queries and updates against a pluggable graph backend. Application developers can pick one of the ready-made connectors or implement the @metreeca/wire-sparql Repository interface to support a new SPARQL backend.

[!IMPORTANT] Transaction Isolation — Determined by the supplied Repository. The framework defers transaction semantics to the backend; each connector documents the level it provides on its factory function.

Installation

Install the framework together with a backend connector from the @metreeca/wire SPARQL connector collection:

npm install @metreeca/keep-sparql
npm install @metreeca/wire-sparql-oxigraph    # or another backend connector

Usage

[!NOTE]

This section introduces essential concepts; for complete coverage, see the API reference.

Wiring a Store

Pass any @metreeca/wire-sparql Repository connector to createSPARQLStore to obtain a fully functional Store:

import { createSPARQLStore } from "@metreeca/keep-sparql";
import { createOxiRepository } from "@metreeca/wire-sparql-oxigraph";

const store = createSPARQLStore(createOxiRepository());

const product = await store.lookup({
	entry: "http://example.com/products/1",
	shape: ProductShape,
	model: {
		name: "",
		price: 0
	}
});

Implementing a Connector

A backend connector is a @metreeca/wire-sparql Repository: implement ask, select, construct, update, execute, and optionally close, lifting backend node values into the shared Term representation with the reference, tagged, and typed constructors. @metreeca/keep-sparql then wraps any such connector into a Store via createSPARQLStore.

See @metreeca/wire-sparql-oxigraph for a complete reference connector.

Verified Backends

This SPARQL connector has been exercised against the @metreeca/keep-suite conformance suite on the backends and versions below.

| Engine | Version | Storage | |------------------------------|----------------------------------------------------------|---------------| | Eclipse RDF4J | 5.3.1 | MemoryStore | | Eclipse RDF4J | 5.3.1 | NativeStore | | Eclipse RDF4J | 5.3.1 | LmdbStore | | Apache Jena Fuseki | 6.1.0 | MemoryDataset | | Apache Jena Fuseki | 6.1.0 | TDB1 | | Apache Jena Fuseki | 6.1.0 | TDB2 | | Oxigraph | 0.5.8 | in-memory | | Oxigraph | 0.5.8 | disk | | QLever | upcoming | disk | | Fluree | upcoming | disk | | Virtuoso | upcoming | disk |

Support

• open an issue to report a problem or to suggest a new feature
• start a discussion to ask a how-to question or to share an idea

License

This project is licensed under the Apache 2.0 License – see LICENSE file for details.