neo4jrestclient check relations

Question

I am using neo4jrestclient with python. I would like to check if two nodes have a specific relation.

For example

alice = gdb.nodes.create(name="Alice", age=30)
bob = gdb.nodes.create(name="Bob", age=25)
alice.labels.add("Person")
bob.labels.add("Person")
alice.relationships.create("Knows", bob)

How can I check if Alice has the "Knows" relation with Bob? I tried to find something from documentation with no luck.

Answer 1

There are many ways to do it. I show below two:

1. Using the the standard neo4jrestclient's API, which might not be the most efficient:

   bob in [rel.end for rel in alice.relationships.all(types=['Knows'])]
   

   Or taking into account only outgoing relationships from alice

   bob in [rel.end for rel in alice.relationships.outgoing(types=['Knows'])]
   

2. Through a Cypher query

   from neo4jrestclient.client import Node
   cypher = "MATCH (a)-[Knows]-(b) WHERE a.name = 'Alice' AND b.name = 'Bob' RETURN b" 
   gdb.query(query, returns=Node)[0][0] == bob