Neo4j双向关系

Question

Is there a way to create bidirectional relationship in Neo4j using Cypher? I would like the relationship to be bidirectional rather than making two unidirectional relationships in both directions For eg:

(A)<-[FRIEND]->(B)

Rather than:

(A)-[FRIEND]->(B)
(A)<-[FRIEND]-(B)

Thanks in advance :)

Answer 1

No, there isn't. All relationships in neo4j have a direction, starting and ending at a given node.

There are a small number of workarounds.

• Firstly, as you've suggested, we can either have two relationships, one going from A to B and the other from B to A.

• Alternatively, when writing our MATCH query, we can specify to match patterns directionlessly, by using a query such as

   MATCH (A)-[FRIEND]-(B) RETURN A, B 

  which will not care about whether A is friends with B or vice versa, and allows us to choose a direction arbitrarily when we create the relationship.

Answer 2

According to this article: Modeling Data in Neo4j: Bidirectional Relationships

The strictly better choice is to create a relationship in an arbitrary direction and not specify the direction when querying:

MATCH (neo)-[:PARTNER]-(partner)

The engine is capable of traversing the edge in either direction. Creating the anti-directional edge is unnecessary and only serves to waste space and traversal time.