I tried to run the query below:
edge = g.V(id).addE("rated").to(g.V(n_id)).next()
but I am getting the error
InvalidRequest: Error from server: code=2200 [Invalid query] message="Could not read the traversal from the request sent. Error was: Could not locate method: DefaultGraphTraversal.addE([rated, [GraphStep(vertex,[{source_id=34897306, source_system=MSI_CLIENT, ~label=person}])]])"
Both g.V(id) and g.V(n_id) is returning vertices and I don’t see any issues with that. Can some one please let me know why I am facing above error ?
1
gremlinpython has a quirk which prevents you from nesting traversals within other traversals in this way. When you nest V() within a traversal, you must use the __ class like so: __.V(). You can import the __ class as from gremlin_python.process.graph_traversal import __.
The below code should work:
from gremlin_python.process.anonymous_traversal import traversal
from gremlin_python.process.graph_traversal import __, GraphTraversalSource
from gremlin_python.driver.driver_remote_connection import DriverRemoteConnection
GRAPH_DB_HOST = "your db host"
GRAPH_DB_USER = "your db user"
GRAPH_DB_PASSWORD = "your db password"
GREMLIN_SEVER_PORT = "8182"
GRAPH_DB_URL = f"ws://{GRAPH_DB_HOST}:{GREMLIN_SEVER_PORT}/gremlin"
g: GraphTraversalSource = traversal().withRemote(
DriverRemoteConnection(GRAPH_DB_URL, 'g',
username=GRAPH_DB_USER,
password=GRAPH_DB_PASSWORD)
)
edge = g.V(id).addE("rated").to(__.V(n_id)).next()