sparql endpoints

The sparql_endpoints tab of the MatWerk workbook currently holds 23 rows. Every row follows the same shape, and that shape is the pattern below: a entity instance carrying the row's identity, denoted by value node nodes that hold its values, and object properties pointing at entities in other tabs.

Generated from the live sheet and MWO 3.0.1 by scripts/gen_patterns.py — regenerate it rather than editing it by hand.

The pattern

+ − Fit ⛶ DagreForceCircle ConcentricTreeGrid

LOD L0 · classes only L1 · + hierarchy L2 · + individuals & object props L3 · + OWL restrictions L4 · + data props & literals L5 · everything except inferred L6 · everything Hidden Group Facets Style: Ontoink Style: Chowlk Style: Graffoo Style: VOWL

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Drag the nodes, change the layout, or use Group to collapse a namespace. The picture is the example only; the declarations and annotations behind it are in module.ttl.

Columns

Column	ROBOT	Property	Meaning
Label	A	rdfs:label	label
Short description	I	obo:IAO_0000235	denoted by
sparql endpoint	I	obo:IAO_0000235	denoted by
License	I	nfdi:NFDI_0000142
Creator(s)	I	obo:BFO_0000051	has part
Creator(s) affiliation	I	obo:BFO_0000051	has part

How to read it

• The entity is typed nfdi:NFDI_0000009 (dataset) and carries only its identity, its label, and links.
• A column marked I does not contain a value — it contains the label of another instance, which ROBOT resolves at build time. That is why every value node needs a unique label, and why a typo produces a silently missing relation rather than an error.
• Columns marked A are literals on the entity itself.

Components (value nodes)

These value-node types live in the workbook's shared req_2 tab but belong to this pattern — they exist to describe it, and are counted by how often this tab references them.

Component	Class	References
sparql endpoint	nfdi:NFDI_0001095	23

Query it

Retrieve instances of this pattern from the MatWerk Knowledge Graph (SPARQL endpoint):

SELECT ?x ?label WHERE { ?x a <https://nfdi.fiz-karlsruhe.de/ontology/NFDI_0000009> ; <http://www.w3.org/2000/01/rdf-schema#label> ?label } LIMIT 10

The rows behind it are curated in the sparql_endpoints tab of the workbook.

Competency questions

The questions this pattern exists to answer. Each is answerable against the published graphs.

1. Which SPARQL endpoints can the MatWerk Knowledge Graph be federated with?
2. What is the endpoint URL of a given knowledge graph, and under which licence is it offered?
3. Who created and maintains a given endpoint's dataset?

Pattern metadata

The Ontology Design Patterns content-ODP annotation schema, in the community's own field order, so a reader who knows ODP pages can read this one without translation.

Field	Value
Name	sparql endpoints
Submitted by	the NFDI-MatWerk consortium
Also Known As	the sparql_endpoints template tab of the NFDI-MatWerk workbook
Intent	To represent a dataset in the MatWerk Knowledge Graph: its identity, the value nodes that describe it, and its links to the other entities the NFDI-MatWerk consortium records.
Domains	research data management; NFDI consortium structure
Competency Questions	Which SPARQL endpoints can the MatWerk Knowledge Graph be federated with?; What is the endpoint URL of a given knowledge graph, and under which licence is it offered?; Who created and maintains a given endpoint's dataset?
Solution description	An entity individual typed nfdi:NFDI_0000009 carries identity and label; each descriptive value is a separate value node individual reached by obo:IAO_0000235 (denoted by); links to other patterns are object properties onto those entities. Identity is a minted IRI msekg:<epoch_ms><counter>, so re-running the pipeline is idempotent.
Reusable OWL Building Block	module.ttl — the example together with the axioms of every term it uses, extracted from the ontology, so the file stands alone
Consequences	Values become reusable and independently addressable, and a value may be shared by many entities. The cost: every I reference resolves by label, so labels must be unique and a typo yields a silently missing relation rather than an error.
Scenarios	“atomRDF Knowledge Graph v0.0.1” is a dataset, with short description “atomRDF KG is a FAIR, RDF-based knowledge graph for atomistic simulation data in metals. It integrates seven published datasets covering materials such as Al, Cu, Fe, W, and Mg, and includes results from molecular statics, molecular dynamics, and DFT calculations. The graph represents grain boundary energies, work of separation, segregation and defect formation energies, elastic constants, and structural data using established materials science ontologies and provenance standards, and is accessible through a SPARQL endpoint.”; sparql endpoint “sparql endpoint of atomRDF Knowledge Graph v0.0.1”; license “CC BY 4.0”.
Known Uses	the MatWerk Knowledge Graph (https://nfdi.fiz-karlsruhe.de/matwerk), published as Virtuoso named graphs
Web References	https://nfdi-matwerk.de · https://ise-fizkarlsruhe.github.io/mwo/
Other References	https://doi.org/10.1002/adem.202502331
Examples (OWL files)	pattern.ttl — one real row of the tab, with its value nodes resolved
Extracted From	the sparql_endpoints tab of the NFDI-MatWerk curation workbook (23 rows at generation time)
Reengineered From	the ROBOT template directives in row 2 of that tab
Has Components	sparql endpoint
Specialization Of	the entity-and-value-node pattern shared by every tab (overview)
Related CPs	dataset

Provenance and versioning

Field	Value
Pattern version	1.0.0
Authors	Harald Sack · Jörg Waitelonis · Ebrahim Norouzi · Hossein Beygi Nasrabadi — the authors of the ontology these patterns are derived from (dcterms:creator of MWO 3.0.1)
Derived from ontology	MatWerk Ontology (MWO) 3.0.1 — http://purls.helmholtz-metadaten.de/mwo/mwo.owl/3.0.1
Reused ontologies	BFO 2020 (http://purl.obolibrary.org/obo/bfo.owl), NFDIcore (https://nfdi.fiz-karlsruhe.de/ontology/), IAO (http://purl.obolibrary.org/obo/iao.owl), RO (http://purl.obolibrary.org/obo/ro.owl)
Ontology licence	CC BY 4.0 (repository); CC0 1.0 declared in the ontology header
Cite the ontology as	Hossein Beygi Nasrabadi, Jörg Waitelonis, Ebrahim Norouzi, Kostiantyn Hubaiev, Harald Sack. NFDI MatWerk Ontology (mwo). Revision: v3.0.1. Retrieved from: http://purls.helmholtz-metadaten.de/mwo/3.0.1
Generated	scripts/gen_patterns.py, 2026-08-04

Formal characterisation

Measure	Value
Consistency	consistent — ROBOT 1.9.10, reasoner HermiT, merged with MWO 3.0.1
DL expressivity	RRESTRCUCINTUNIVRESTREROIF — measured on the pattern together with a STAR module of exactly the terms it uses, so the figure describes this pattern rather than the whole ontology
Axioms / logical axioms	17 / 6
Classes / individuals	6 / 6

Consistency

pattern.ttl is checked against MWO 3.0.1 with ROBOT (--reasoner hermit) — the same reasoner process_spreadsheets runs over every generated module. A pattern that contradicts the ontology fails the documentation build.