Neo4j cyper query: How to travese - neo4j

Question

I am trying to learn neo4j, so I just took a use case of a travel app to learn but I am not sure about the optimal way to solve it. Any help will be appreciated.
Thanks in advance.
So consider a use case in which I have to travel from one place (PLACE A) to other (PLACE C) by train, but there is no direct connection between the two places. And so we have to change our train in PLACE B.
Two places are connected via a relation IS_CONNECTED relation. refering to green nodes in the image
And then if there is an is_connected relation between two place then there will be an out going relation i.e. CONNECTED_VIA to a common train from both the node which implies how they are connected referring to red nodes in image
my question is how are we suppose to know that we have to change the station from place b
My understanding is:
We will check where the two places are connected via IS_CONNECTED relationship
match (start:place{name:"heidelberg"}), (end:place{name:"frankfurt"})
MATCH path = (start)-[:IS_CONNECTED*..]->(end)
RETURN path
this will show that these two places are connected
Then we will see that if place A and place c are directly connected or not by the query
match (p:place{name:"heidelberg"})-[:CONNECTED_VIA]->(q)<-[:CONNECTED_VIA]-(t:place{name:"frankfurt"})
return q
And this will return nothing because there is no direct connections
My brain stopped functioning after this. I am trying to figure how from past 3 days. I am sorry I look ao confused
Please click here for the image of what i am referring

Answer 1

You'll want to use variable-length relationships in your :CONNECTED_VIA match, and then get the :Place nodes that are in your path. And it's usually a good idea to use an upper bound, whatever makes sense in your graph.
Then we can use a filter on the nodes in your path to only keep the ones that are :Place nodes.
match path = (p:place{name:"heidelberg"})-[:CONNECTED_VIA*..4]-(t:place{name:"frankfurt"})
return path, [node in nodes(path)[1..-1] where node:Place] as connectionPlaces
And if you're only interested in the shortest paths, you may want to check the shortestPath() or shortestPaths() functions.
One last thing to note...when determining if two locations are connected, if all you need is a true or false if they're connected, you can use the EXISTS() function to return whether such a pattern exists:
match (start:place{name:"heidelberg"}), (end:place{name:"frankfurt"})
return exists((start)-[:IS_CONNECTED*..5]->(end))