Query to find node which have only one vertex in common
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Harshit Sharma
Mar 31, 2021, 1:01:26 PM3/31/21
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I have the following vertices -
Person1 -> Device1 <- Person2
| |
v v
Email1 <- Person3
Now I want to write a gremlin query (janusgraph) which will give me all persons connected to the device(only) with which person1 is connected.
So according to the above graph, our output should be - [person2].
Person3 is not in output because person3 is also connected with "Email1" of "Person1"
Harshit Sharma
Mar 31, 2021, 1:15:42 PM3/31/21
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Updated graph
Person1 -> Device1 <- Person2
^
| |
v
Email1 <- Person3
Harshit Sharma
Apr 1, 2021, 12:11:17 AM4/1/21
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Bassem Naguib
Apr 1, 2021, 3:45:12 AM4/1/21
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It helps a lot when you give us a traversal that creates the graph. Like so
g.addV('person').property('name', 'Person1').as('p1').
addV('person').property('name', 'Person2').as('p2').
addV('person').property('name', 'Person3').as('p3').
addV('device').as('d1').
addV('email').as('e1').
addE('HAS_DEVICE').from('p1').to('d1').
addE('HAS_EMAIL').from('p1').to('e1').
addE('HAS_DEVICE').from('p2').to('d1').
addE('HAS_DEVICE').from('p3').to('d1').
addE('HAS_EMAIL').from('p3').to('e1')
addV('person').property('name', 'Person2').as('p2').
addV('person').property('name', 'Person3').as('p3').
addV('device').as('d1').
addV('email').as('e1').
addE('HAS_DEVICE').from('p1').to('d1').
addE('HAS_EMAIL').from('p1').to('e1').
addE('HAS_DEVICE').from('p2').to('d1').
addE('HAS_DEVICE').from('p3').to('d1').
addE('HAS_EMAIL').from('p3').to('e1')
The following traversal will give you the person vertices that are connected to "Person1" via one or more "device" vertices and not connected via any other type of vertices.
g.V().has('person', 'name', 'Person1').as('p1').
out().as('connector').
in().where(neq('p1')).
group().
by().
by(select('connector').label().fold()).
unfold().
where(
select(values).
unfold().dedup().fold(). // just in case the persons are connected by multiple devices
is(eq(['device']))
).
select(keys)
out().as('connector').
in().where(neq('p1')).
group().
by().
by(select('connector').label().fold()).
unfold().
where(
select(values).
unfold().dedup().fold(). // just in case the persons are connected by multiple devices
is(eq(['device']))
).
select(keys)
I hope this helps.
Harshit Sharma
Apr 1, 2021, 5:26:31 AM4/1/21
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Actually, I tried this same query for Email, by replacing 'device' with 'Email'. So in that case it is not working.
Harshit Sharma
Apr 1, 2021, 5:27:10 AM4/1/21
to Gremlin-users
g.V().has('person', 'name', 'Person1').as('p1').
out().as('connector').
in().where(neq('p1')).
group().
by().
by(select('connector').label().fold()).
unfold().
where(
select(values).
unfold().dedup().fold(). // just in case the persons are connected by multiple devices
is(eq(['email']))out().as('connector').
in().where(neq('p1')).
group().
by().
by(select('connector').label().fold()).
unfold().
where(
select(values).
unfold().dedup().fold(). // just in case the persons are connected by multiple devices
).
select(keys)
Harshit Sharma
Apr 1, 2021, 6:32:28 AM4/1/21
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It is working fine now.. thanks
Message has been deleted
Harshit Sharma
Jul 28, 2021, 9:16:17 AM7/28/21
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Is it required to use where(neq('p1')) ? i tried without this and answer is still same.
Is it possible to optimize this step - group().by().by(select('connector').label().fold()) ?because as per profile() this step is taking majority of the time and in case of large data this query becomes slow.
Is it possible to optimize this step - group().by().by(select('connector').label().fold()) ?because as per profile() this step is taking majority of the time and in case of large data this query becomes slow.
On Thursday, April 1, 2021 at 1:15:12 PM UTC+5:30 bass...@gmail.com wrote:
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