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RDF Ontology Examples and Configuration

This page covers how to enable ontology-guided KG extraction and provides example ontology files in Turtle format.

When ontologies are enabled, they guide KG extraction for both property graph databases and RDF triple stores — ontologies are not specific to RDF stores.

Enabling ontologies

Add these variables to your .env file:

# Enable ontology-guided extraction
USE_ONTOLOGY=true

# Choose one of the three path options below:

# Single ontology file
ONTOLOGY_PATH=../schemas/my_ontology.ttl

# Multiple ontology files (comma-separated)
ONTOLOGY_PATHS=../schemas/company_classes.ttl,../schemas/company_properties.ttl,../schemas/common_ontology.ttl

# Directory of ontology files (loads all .ttl files in the directory)
ONTOLOGY_DIR=../schemas/

ONTOLOGY_PATHS takes precedence over ONTOLOGY_PATH; ONTOLOGY_DIR is used when neither is set.

Schema file locations by install type

Source checkout — schemas/ lives at the monorepo root, one level above the flexible-graphrag/ subdirectory where .env and main.py live. Use ../schemas/... as shown above (matches env-sample.txt).

PyPI install — copy the schemas/ directory from the repository to the parent of the directory where your .env lives, so the same ../schemas/... paths work without changing your .env. Alternatively, place schemas/ alongside .env and change the paths to ./schemas/....

# Ontology format (auto-detected from extension; set explicitly if needed)
ONTOLOGY_FORMAT=turtle          # turtle | rdfxml | ntriples | nquads

# Schema strictness
STRICT_SCHEMA_VALIDATION=false  # false (default) = ontology guides but LLM can go beyond it
                                 # true = only extract types explicitly defined in the ontology

Example 1: FOAF ontology

A standard vocabulary for people and organizations.

File: schemas/foaf_ontology.ttl

@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix owl:  <http://www.w3.org/2002/07/owl#> .

# Classes (entity types)
foaf:Person a owl:Class ;
    rdfs:label "Person" ;
    rdfs:comment "A human being" .

foaf:Organization a owl:Class ;
    rdfs:label "Organization" ;
    rdfs:comment "A collective entity" .

foaf:Project a owl:Class ;
    rdfs:label "Project" ;
    rdfs:comment "A project or initiative" .

# Properties (relation types)
foaf:name a owl:DatatypeProperty ;
    rdfs:domain foaf:Person ;
    rdfs:range  rdfs:Literal ;
    rdfs:label  "name" .

foaf:workplaceHomepage a owl:ObjectProperty ;
    rdfs:domain foaf:Person ;
    rdfs:range  foaf:Organization ;
    rdfs:label  "workplaceHomepage" ;
    rdfs:comment "Person works at Organization" .

foaf:knows a owl:ObjectProperty ;
    rdfs:domain foaf:Person ;
    rdfs:range  foaf:Person ;
    rdfs:label  "knows" .

foaf:topic_interest a owl:ObjectProperty ;
    rdfs:domain foaf:Person ;
    rdfs:range  foaf:Project ;
    rdfs:label  "topic_interest" .

foaf:member a owl:ObjectProperty ;
    rdfs:domain foaf:Person ;
    rdfs:range  foaf:Organization ;
    rdfs:label  "member" .

.env setup for this ontology:

USE_ONTOLOGY=true
ONTOLOGY_PATH=../schemas/foaf_ontology.ttl

Example 2: Company ontology (multi-file)

The built-in company ontology included with Flexible GraphRAG splits classes and properties into separate files.

Classes file — schemas/company_classes.ttl (at repo root):

@prefix company: <http://example.org/company/> .
@prefix common:  <https://integratedsemantics.org/flexible-graphrag/common#> .
@prefix owl:     <http://www.w3.org/2002/07/owl#> .
@prefix rdfs:    <http://www.w3.org/2000/01/rdf-schema#> .

company:Employee a owl:Class ;
    rdfs:subClassOf common:Person ;
    rdfs:label "Employee" .

company:Department a owl:Class ;
    rdfs:label "Department" .

company:Company a owl:Class ;
    rdfs:label "Company" .

company:Project a owl:Class ;
    rdfs:label "Project" .

company:works_for a owl:ObjectProperty ;
    rdfs:domain common:Person ;
    rdfs:range  company:Company ;
    rdfs:label  "works_for" .

company:part_of a owl:ObjectProperty ;
    rdfs:domain company:Department ;
    rdfs:range  company:Company ;
    rdfs:label  "part_of" .

.env setup for multi-file company ontology:

USE_ONTOLOGY=true
ONTOLOGY_PATHS=../schemas/company_classes.ttl,../schemas/company_properties.ttl,../schemas/common_ontology.ttl

Example 3: Custom domain ontology

A minimal template for any domain.

File: schemas/my_domain.ttl

@prefix my:   <https://example.org/my-domain/> .
@prefix owl:  <http://www.w3.org/2002/07/owl#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd:  <http://www.w3.org/2001/XMLSchema#> .

# --- Classes ---

my:Product a owl:Class ;
    rdfs:label "Product" .

my:Supplier a owl:Class ;
    rdfs:label "Supplier" .

my:Category a owl:Class ;
    rdfs:label "Category" .

# --- Object properties (entity → entity) ---

my:supplied_by a owl:ObjectProperty ;
    rdfs:domain my:Product ;
    rdfs:range  my:Supplier ;
    rdfs:label  "supplied_by" .

my:belongs_to a owl:ObjectProperty ;
    rdfs:domain my:Product ;
    rdfs:range  my:Category ;
    rdfs:label  "belongs_to" .

# --- Datatype properties (entity → literal) ---

my:sku a owl:DatatypeProperty ;
    rdfs:domain my:Product ;
    rdfs:range  xsd:string ;
    rdfs:label  "sku" .

my:unit_price a owl:DatatypeProperty ;
    rdfs:domain my:Product ;
    rdfs:range  xsd:decimal ;
    rdfs:label  "unit_price" .

.env setup:

USE_ONTOLOGY=true
ONTOLOGY_PATH=../schemas/my_domain.ttl
STRICT_SCHEMA_VALIDATION=false