Stefan Plantikow

Cypher is a property graph query language that provides expressive and efficient querying of graph data. Originally designed and implemented within the Neo4j graph database, it is now being used by several industrial database products, as well as open-source and research projects.

Since 2015 Cypher has been an open, evolving language, with the aim of becoming a fully-specified standard with many independent implementations. We provide a brief introduction to Cypher, the property graph model and the openCypher project, and then describe extensions – either actively being developed or under discussion – which will be incorporated into Cypher in the near future. These include (i) making Cypher into a fully compositional graph query language, by supporting multiple graphs and allowing graphs to be returned from queries; (ii) allowing for more complex patterns (based on regular path queries) to be expressed; and (iii) allowing for different pattern matching semantics – homomorphism, relationship isomorphism (the current default) or node isomorphism – to be configured at a query-by-query level.