Live from NODES 2026 – A Metamodel for Neo4j: How Deutsche Bahn Describes Meaning and Rules

Neo4j’s schema-free property graph model is powerful, but it leaves important semantic questions open: What does a label, property, or relationship type mean? Which properties should labels or types have, and which label combinations should relationship types connect? This talk introduces a lightweight metamodel and ontology framework that defines these meanings directly inside the Neo4j database, keeping semantics available, synchronized, and compatible with evolving or non-conforming graphs. [1]

The approach follows a practical “maybe, should, could” mindset rather than a rigid logic system, inspired by duck typing and open-world thinking. It also shows how our opensource GraphEditor supports the metamodel through semantic browsing, editing, visualization, parameterized queries, full-text search, persistent graph perspectives, and styling. Finally, the talk compares this approach with RDF 1.2.

Speaker

Jörg Baach & Georg Schwarz