Andy Seaborne afs

SHACL Rules

SHACL rules infer new triples. The input is a data graph and a shape graph with rules, the output is a graph of inferred triples that do not occur in the data graph.

Whether, and how, the output graph is added back into the data graph is a separate decision.

Notes

@@Datalog-ish then a collection of "run once rules easy for defaulting"

https://cs.emis.de/LNI/Proceedings/Proceedings241/383.pdf

Table: students: {[id, name, major, year, . . . ]}
Table exams: {[sid, course, curriculum, date, . . . ]}

    select s.name,e.course
    from   students s,exams e 
    where  s.id=e.sid and
 e.grade=(select min(e2.grade)

SHACL Rules

SHACL rules infer new triples. The input is a data graph and a shapes graph which has rules; the output is a graph of inferred triples.

Whether, and how, the output graph is added back into the data graph is not part of the SHACL rules process. If being run to enrich the data graph, the process can be done inside a transaction updating the data graph.

The rule system is also capable of triple pattern matching - what datalog calls a "query" - where only necessary rules are run. (This is "backward chaining")

Once repeated application of rules is considered, there does not seem to be useful subsets of features. Fortunately, simple evaluation of (positive i.e. without negation) datalog is not a major piece of implementation. Run rules until no change; the implementation does not need to inspect the rule set structure. The literature has several better algorithms where implementation isn't partic

	PREFIX : <#>
	PREFIX fuseki: <http://jena.apache.org/fuseki#>
	PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
	PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
	PREFIX ja: <http://jena.hpl.hp.com/2005/11/Assembler#>
	PREFIX tdb2: <http://jena.apache.org/2016/tdb#>

	## RDFS+TDB2 Dataset

	[] rdf:type fuseki:Server ;

	<?xml version="1.0" encoding="utf-8"?>
	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
	<html>
	<head>
	<title>SHACL-C Grammar</title>
	<link rel="stylesheet" type="text/css" href="https://www.w3.org/StyleSheets/TR/base.css" />
	<link rel="stylesheet" type="text/css" href="https://www.w3.org/2001/sw/DataAccess/rq23/local.css" />
	</head>
	<body>
	<!-- GRAMMAR -->

	## Build for Apache Jena
	## maven with added dependencies for running Cypress and the UI part of the build.
	## Run this container with the Jena mounted on /jena

	FROM 'maven:3.9.8-eclipse-temurin-21-jammy' AS base

	ENV DEBIAN_FRONTEND=noninteractive

	RUN apt update

	@prefix dash: <http://datashapes.org/dash#> .
	## @prefix owl: <http://www.w3.org/2002/07/owl#> .
	@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
	@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
	@prefix sh: <http://www.w3.org/ns/shacl#> .
	## @prefix tosh: <http://topbraid.org/tosh#> .
	## @prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

	dash:ListNodeShape
	a sh:NodeShape ;

	public static void main(String...args) {
	Model model = ModelFactory.createDefaultModel();
	Resource subject1 = ResourceFactory.createResource("http://example/s1");
	Resource subject2 = ResourceFactory.createResource("http://example/s2");
	Property property = ResourceFactory.createProperty("http://example/p");
	Long longValue = 6L;
	model.addLiteral(subject1, property, ResourceFactory.createTypedLiteral(longValue.toString(), XSDDatatype.XSDlong));
	model.addLiteral(subject2, property, longValue);
	RDFWriter.source(model).lang(Lang.TTL).output(System.out);
	}

	/*
	* Licensed to the Apache Software Foundation (ASF) under one
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	you may not use this file except in compliance with the License.
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