Why did I get the “Kernel API returned non-existent relationship type: -1” exception?

In rare situations, the Neo4j Bolt driver throws an IllegalStateException. The top part of the stack appears as: java.lang.IllegalStateException: Kernel API returned non-existent relationship type: -1 at org.neo4j.kernel.impl.factory.GraphDatabaseFacade.getRelationshipTypeById(GraphDatabaseFacade.java:991) Under the covers, this is what happens. The getRelationshipTypeById(int type) method is… Read more →

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Comparing relationship properties within a path

You want to compare relationship-properties of a path, either by a global value or parameter, or with each other within a path. Basic model: (:Person {person_id:’123′})-[:FRIEND {date:’1972-01-01′}]->(m:Person {person_id:’456′}) Make sure to have an constraint OR index on your nodes: Constraint… Read more →

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