◆ Semantic Web Catalogue

Design issue

Data model

What shape is the data?

tension
Flexible graphs against strict structure: RDF against property graphs against tables.
also
Model, Abstract syntax
scheme
design issues

Threads (2)

Long-running problems under this issue, told step by step. All threads.

  • Graphs, tables and property graphs 1968–2026 open 11 steps

    What is the right shape for connected data: tables, triples, or graphs whose nodes and edges carry properties?

  • Statements about statements 1999–2026 largely settled 7 steps

    How do you say who made a statement, when, and how sure they are, in a data model built from single statements?

Who answered it

This issue's row of the map: which traditions' works mainly answer it, and the earliest from each.

traditionworksearliest
Hypertext
Knowledge representation 9 Semantic network 1956
Databases 11 Canada Geographic Information System 1963
Machine learning
Web standards 9 Meta Content Framework Using XML 1997
Search 7 Meta Content Framework 1995
Social web
Open knowledge
Decentralized web 2 IPLD
Libraries, archives and museums 6 FRBR 1998
Life sciences
Media 1 Discogs 2000
Geospatial 1 Canada Geographic Information System 1963
Commerce and supply chain 1 EPCIS 2007
Government and law
Finance
Industry and engineering 2 STEP 1994

10 of 17 traditions have taken up this question as a work's main issue; a work in several traditions counts in each. Same counts as the full map.

Timeline

Works on this question, its main or a secondary one, each shown once in date order; filter by tradition to follow one community. Bars run from start to end where both are known; marks people, projects and organizations still active. 8 entries have no date and are not shown. Hover over or focus an entry to draw its links. Scroll sideways, or use the decades above.

Lineage (37)

Works whose main question this is, by type, oldest first.

Concepts 9

  • Semantic network 1956 concept formalism

    Graph of concepts joined by labelled relations, used to represent meaning; first proposed by Richard Richens in 1956 and developed by Quillian and others in the 1960s.

  • Relational model 1969 concept formalism

    Model of data as relations, that is tables of rows with named columns, queried by declarative operations on whole sets; proposed by E.F. Codd and the basis of SQL databases.

  • Frames 1974 concept formalism

    Knowledge structures of slots with default values describing stereotyped situations, proposed by Marvin Minsky in 1974.

  • Entity–relationship model 1976 concept formalism

    Way of modelling a domain as entities, their attributes and the relationships between them, drawn as ER diagrams; introduced by Peter Chen in 1976 as a unified view of the network, relational and entity-set models.

  • Named graph 2005 concept formalism

    Set of triples given its own URI, so that statements can be made about the set, which is how provenance and context are recorded; stored as quads.

  • Knowledge graph concept formalism

    Graph of entities and the relations between them, used to integrate and query data; the term spread after Google's 2012 Knowledge Graph.

  • Labeled property graph concept formalism

    Graph model in which nodes and relationships carry labels and key–value properties; the model behind Neo4j and GQL, and the main rival to RDF for graph data.

  • Merkle DAG concept formalism

    Graph of data blocks in which each block links to others by their content hash, so any change produces new hashes all the way up; a generalisation of the Merkle tree.

  • Semantic triple concept formalism

    The subject–predicate–object statement that is the basic unit of RDF.

Writings 10

Standards 13

  • STEP 1994 standard

    ISO's family of standards for describing manufactured products so CAD, manufacturing and archive systems can exchange them, begun in 1984 and first published in 1994–95; its EXPRESS schema language is an early example of a formal shared data model across an industry.

  • Meta Content Framework 1995 standard

    Format for describing the structure and metadata of websites, developed by R.V. Guha at Apple and later submitted to the W3C with Tim Bray as an XML application.

  • FRBR 1998 standard ★ seminal

    Functional Requirements for Bibliographic Records: IFLA's conceptual model of the bibliographic universe as entities and relationships, separating the work from its expressions, manifestations and items; its final report was published in 1998.

  • CIDOC Conceptual Reference Model 1999 standard ★ seminal

    Ontology for museum and cultural heritage documentation from ICOM's documentation committee, first issued in 1999 and an ISO standard since 2006. It describes objects through the events in their history, such as production, acquisition and movement, so that records from different institutions can be integrated.

  • RDF 1999 standard ★ seminal

    Data model that describes resources as subject–predicate–object statements identified by URIs. It became a W3C Recommendation in 1999 and was revised as RDF 1.1 in 2014.

  • Topic Maps 2000 standard

    ISO standard for representing knowledge as topics, associations and occurrences; similar in expressive power to RDF and developed alongside it.

  • ISO 15926 2003 standard

    ISO standard for integrating the life-cycle data of process plants, including oil and gas facilities, with a generic data model (Part 2, 2003) and reference data libraries; Part 8 implements it in OWL and RDF.

  • FRBRoo 2006 standard

    Formal ontology joining the librarians' FRBR model with the museums' CIDOC CRM, begun in 2006, so that bibliographic and museum records share one model.

  • EPCIS 2007 standard

    GS1 standard, first ratified in April 2007, for sharing events in a product's journey through supply chains: what was seen, when, where and why. Version 2.0 (June 2022) added JSON-LD, a REST API and GS1 Digital Link URIs.

  • Records in Contexts 2016 standard

    The International Council on Archives' standard for archival description as a graph of records, agents, activities and their relations, with a conceptual model and an ontology (RiC-O). Work began in 2012, a draft followed in 2016, and version 1.0 was released in 2023–2024; it extends and replaces the ICA's four earlier description standards, including ISAD(G).

  • IFLA Library Reference Model 2017 standard

    IFLA's 2017 conceptual model of bibliographic information, which consolidates FRBR and its companion models for authority and subject data.

  • RDF 1.2 2026 standard

    Revision of RDF that adds triple terms, so a statement can itself be the object of another statement; it grew out of RDF-star. Its core spec became a W3C Candidate Recommendation in April 2026.

  • IPLD standard

    Data model for linking data by content hash rather than by location; the data layer under IPFS, and the basis of AT Protocol's repository format.

Projects 5

  • Canada Geographic Information System c. 1963–c. 1989 project

    Early geographic information system built for the Government of Canada from the early 1960s to store and analyse the Canada Land Inventory; it ran until the late 1980s.

  • Discogs 2000 project

    User-built database of music releases and marketplace, launched in November 2000; it lists every pressing and edition, with more than 19 million releases by 2026.

  • Neo4j 2007 project

    Property-graph database queried with the Cypher language; begun as an open-source project in Sweden in 2007, with version 1.0 in 2010.

  • Freebase 2007–2016 project ★ seminal

    Collaboratively edited knowledge graph built by Metaweb and bought by Google in 2010. It fed Google's Knowledge Graph, and its data was offered to Wikidata when it closed in 2016.

  • Google Knowledge Graph 2012 project

    Google's knowledge base of entities and their relations, launched in 2012 and built partly from Freebase.

Also bears on this (19)

Concepts 3

  • Linked Data 2006 concept principle

    Way of publishing data on the Web with URIs, HTTP and RDF, so that data sets link to one another the way documents do.

  • GraphRAG 2024 concept technique

    Retrieval-augmented generation in which a language model answers from a knowledge graph built over the source texts, rather than from isolated text chunks.

  • Triplestore concept technique

    Database built to store RDF triples and answer SPARQL queries; Virtuoso is one example.

Writings 7

Standards 6

  • MARC 1965 standard ★ seminal

    MAchine-Readable Cataloging: formats for library catalogue records, developed by Henriette Avram at the Library of Congress between 1965 and 1968 so that libraries could share records by computer; a US national standard by 1971 and international by 1973. MARC 21 (1999) is still the predominant format.

  • Music Ontology 2007 standard

    RDF vocabulary for music, first released in 2007, describing artists, works, recordings and releases, and the performances and recordings that connect them as events in time. It reuses FRBR's split between a work and its expressions, and FOAF for people.

  • BIBFRAME 2012 standard

    Library of Congress model for bibliographic data based on Linked Data, designed to replace the MARC formats; work began in 2012 and version 2.0 followed in 2016.

  • Semantic Sensor Network Ontology 2017 standard

    Joint W3C and OGC ontology, a Recommendation of 19 October 2017, for describing sensors, actuators, observations and samples, with the lightweight SOSA core for simple use; a 2023 edition has been in draft since September 2025.

  • Common Information Model (electricity) standard

    The electricity industry's shared model of power networks, adopted by the IEC, so grid operators' software can exchange data about lines, equipment and measurements; its profiles are exchanged as RDF, including between Europe's transmission operators.

  • Europeana Data Model standard

    Europeana's RDF model for cultural heritage metadata. It reuses Dublin Core, SKOS and OAI-ORE so that each provider's own description is kept alongside Europeana's additions; it replaced the flat Europeana Semantic Elements.

Projects 3

  • WordNet 1985 project ★ seminal

    Lexical database of English begun in 1985 at Princeton's Cognitive Science Laboratory under George A. Miller: nouns, verbs and adjectives grouped into sets of synonyms linked by relations such as broader and part-of. It became a shared vocabulary for language processing and for knowledge bases such as YAGO.

  • YAGO 2007 project

    Knowledge base built at the Max Planck Institute for Informatics that combines facts from Wikipedia with WordNet's taxonomy (later with schema.org's); with DBpedia, one of the first large knowledge bases extracted from Wikipedia.

  • DBpedia 2007 project ★ seminal

    Project that extracts structured data from Wikipedia infoboxes and publishes it as Linked Data; an early hub of the Linked Open Data cloud.

People and organizations (33)

Linked to works on this question; the number counts those works.

World Wide Web Consortium (4) · ISO (3) · R.V. Guha (3) · Edgar F. Codd (2) · Google (2) · Martin Doerr (2) · Olaf Hartig (2) · Peter Chen (2) · Aidan Hogan · Amit Singhal · Andy Seaborne · Claudio Gutiérrez · Colin Evans · Gregg Kellogg · GS1 · International Council of Museums · International Council on Archives · Jamie Taylor · Kevin Lewandowski · Kurt Bollacker · Markus Lanthaler · Marvin Minsky · Metaweb · Ora Lassila · Pat Hayes · Pierre-Antoine Champin · Praveen Paritosh · Ralph Swick · Richard Cyganiak · Roger Tomlinson · M. Ross Quillian · Tim Bray · Tim Sturge