Update property relation with py2neo neo4j

Question

I'm trying to check if a relation between two nodes exists but i get this error:

raise TypeError("Nodes for relationship match end points must be bound") TypeError: Nodes for relationship match end points must be bound

below my code:

graph = Graph(user='neo4j')

src = Node(src_type, internal_id=int(src_id))
dst = Node(dst_type, internal_id=int(dst_id))

src_voted_dst = Relationship(src, "VOTED", dst)

for elem in graph.match(start_node=src, rel_type="VOTED", end_node=dst, bidirectional=True):
    elem.properties["vote"] = elem.properties["vote"] + 1
    elem.push()
    break
else:
    src_voted_dst.properties["vote"] = 1
    graph.merge(src_voted_dst)

Answer 1

In the code:

src = Node(src_type, internal_id=int(src_id))
dst = Node(dst_type, internal_id=int(dst_id))

src and dst are created locally, but not bound to these nodes in the database. Bind the local nodes to the database with merge:

db_src = graph.merge(src)
db_dst = graph.merge(dst)

Then match should then work:

for elem in graph.match(db_src, "VOTED", db_dst)

(note that elem.properties["vote"] will not work, there should be something link elem.start_node()["vote"] or elem.end_node()["vote"])