I am trying to return a single nested object which combines data from multiple vertices using Gremlin.
Example Data Model:
For the above data model I would like to return a list of externalReferences for a given referenceSignal and system.
I have been able to return the vertices I want data from by using .select() steps but I am unsure how I can manipulate the returned vertices into one single object.
Current query:
g.V().has('id', 'SYSTEM_ID').hasLabel('system').as("system")
.in("partOf").hasLabel('component').as("component")
.in("partOf").hasLabel('signal').as("signal")
.where(out("instanceOf").hasLabel('referenceSignal').has("name", "REF_SIGNAL_NAME")).in("describes").hasLabel('externalReference').as("externalReference")
.select('system', 'component', 'signal', 'externalReference')
Output:
[{system=v[2776], component=v[2780], signal=v[2797], externalReference=v[2843]}, {system=v[2776], component=v[2785], signal=v[2802], externalReference=v[2848]}]
I want the returned data to be in the follow format:
{
"system_id": "{system_id from the system vertex}",
"system_name": "{system_name from the system vertex}",
"components": [ # Array of components adjacent to system
{
"component_id": "{component_id from the component vertex}",
"component_name": "{component_name from the component vertex}",
"signals": [ # Array of signals adjacent to component
{
"signal_id": "{signal_id from the signal vertex}",
"signal_name": "{signal_name from the signal vertex}",
"external_reference_id": "{external_reference_id from the external reference vertex adjacent to the signal}"
}
]
}
]
}
Related
I want to get nested objects in the form of
{ country :
{code:'IN',states:
{code:'TG',cities:
{code:'HYD',malls:
{[shopping-mall1],[shopping-mall2],.....}
},
{code:'PKL',malls:
{[shopping-mall1],[shopping-mall2],.....}
}
},
{code:'AP',cities:
{code:'VJY',malls:
{[shopping-mall1],[shopping-mall2],.....}
}
}
}
}
MY graph is in format
vertex: country ---> states ---->cities ---> mallls
edges: (type:'state') ('type','city')
ex: inE('typeOf').outV().has('type','state') move to next vertex "states".
next same inE('typeOf').outV().has('type','city') moves to "city" vertex. then "malls" vertex .
And tired to write the code, some vertex has no cities i have an error that situavation."
error
The provided traverser does not map to a value: v[8320]->[JanusGraphVertexStep(IN,[partOf],vertex), HasStep([type.eq(city)]), JanusGraphPropertiesStep([code],value)]
Thats why i am using coalesce because some state has not an edge 'inE('partOf').outV().has('type','city')' means no city
.by(coalesce(select('states').inE('partOf').outV().has('type','city'))
My query
g.V().hasLabel('Country').has('code','IN')
.project('country')
.by(project('code','states')
.by(values('code'))
.by(inE('partOf').outV().has('type','state').has('code').as('states').
project('code','cities')
.by(select('states').values('code'))
.by(coalesce(select('states').inE('partOf').outV().
has('type','city').has('code').as('cities').
project('code','malls')
.by(select('cities').values('code'))
.by(coalesce(select('cities').inE('partOf').outV().
has('type','malls').valueMap(),constant(0))),
constant(0)))))
But the result is
{country={code=IN, states={code=DD, cities=0}}}
here i am getting one state 'DD' and that state is no city,so it gives 'cities = 0".
the above result is only one state is coming, i want all states, cities and malls in each city.
Please update query or change query
In order to collect all the results you should use .fold() traversal which returns a list of the collected traversals. without fold you will get only the first traversal like in your example.
In order to keep the types the same I changed the constant to [] instead of 0.
It was also not clear if the "type" property is on the edge or the vertex. I find it more appropriate to have it on the edge, so I fixed it as well by moving the has('type',...) between the inE() and outV().
Last, you don't need to "store" the traversal using "as" and then "select" it.
This query should give you the required result:
g.V().hasLabel('Country').has('code','IN')
.project('country')
.by(project('code','states')
.by(values('code'))
.by(inE('partOf').has('type','state').outV().has('code')
.project('code','cities')
.by(values('code'))
.by(coalesce(inE('partOf').has('type','city').outV().has('code')
.project('code','malls')
.by(values('code'))
.by(coalesce(
inE('partOf').has('type','malls').outV().valueMap(),
constant([])).fold()),
constant([])).fold())
.fold()))
I am new to meteor and mongoDB and have been searching for an answer to this question for some time without any luck.
I have multiple documents in MongoDB similar to the one below:
{
"_id" : ObjectId("5abac4ea0c31d26804421371"),
"Points" : [
{
"Value" : 6.869752766626993,
"Time" : 1522284528946
},
{
"Value" : 3.9014587731230477,
"Time" : 1522284543946
},
{
"Value" : 1.2336926618519772,
"Time" : 1522284558946
},
{
"Value" : 6.504837583667155,
"Time" : 1522284573946
},
{
"Value" : 9.824138227740864,
"Time" : 1522284588946
},
{
"Value" : 9.707480757899235,
"Time" : 1522284603946
},
{
"Value" : 4.6122167850338105,
"Time" : 1522284618946
}
]
}
How can I implement a query in meteor that returns an array containing all the Points from all documents with 'Time' field greater than certain value?
As Jankapunkt has pointed out in his comment, it might be a lot easier and better if you created a new collection Points where each document includes only Value and Time attributes. The given example would then become seven separate documents rather than a single array.
It does nevertheless happen, that we want to query documents according to some inner values, e.g. attributes in objects in arrays.
Taken from the mongodb documentation on querying embedded documents, we can just use dot notation for this.
If you do not know the index position of the document nested in the array, concatenate the name of the array field, with a dot (.) and the name of the field in the nested document.
Such as for your question (assuming Points to be the name of your collection):
db.points.find( { 'Points.Time': { $gte: 123412341234 } } )
Which looks almost identical in Meteor:
Points.find({ 'Points.Time': { $gte: 123412341234 } })
I'm trying to make a graph from a csv file, but I'm not being able to add additional relationship in the existing nodes.
My actual code is:
USING PERIODIC COMMIT 10000
LOAD CSV FROM 'my_file.csv' AS line
MERGE (p:Title { title: line[0]})
MERGE (a:Author { name: line[1]})
MERGE (a)-[:COLABORATE_IN]->(p)
WITH line WHERE line[2] IS NOT NULL
MERGE (b:Author {name: line[2]})
MERGE (b)-[:COLABORATE_IN]->(p) //not working
RETURN line[2]
It should be a simple, It creates well the nodes and the firsts relationships, but for the line[2] it just create the relationships for new nodes. What could I do?
Thanks
Everything that is not piped in the WITH clause is not available to the next part of the query :
MERGE (a:Author { name: line[1]})
MERGE (a)-[:COLABORATE_IN]->(p)
WITH line WHERE line[2] IS NOT NULL
// p is no more available here
Just add the p identifier to make it available in the remaining part of the query :
USING PERIODIC COMMIT 10000
LOAD CSV FROM 'my_file.csv' AS line
MERGE (p:Title { title: line[0]})
MERGE (a:Author { name: line[1]})
MERGE (a)-[:COLABORATE_IN]->(p)
WITH p, line
WHERE line[2] IS NOT NULL
MERGE (b:Author {name: line[2]})
MERGE (b)-[:COLABORATE_IN]->(p) //not working
RETURN line[2]
I'm using GRAPH_TRAVERSAL to get the path from a list of nodes to the head of the tree. This works perfectly except when the example happens to be the head of the tree. In this case, the edgeCollection doesn't have an inbound entry for this object so it doesn't appear in the results.
FOR v IN GRAPH_TRAVERSAL('gdp2',
[{_id:'pmsite/14419285155'}],
'inbound',{edgeCollection:'child'})
RETURN v
The result is an empty list: []
Is there a way I can guarantee that the starting node is on the list? It would be a pain to go through the list of examples to segregate which ones are at the head of a tree.
The problem is within the query itself. It contains a subtle error which is hard to spot:
[{_id:pmsite/14419285155}],
This is missing the quotes around pmsite/14419285155.
What this query realy does is to devide (probably the count of) the collection pmsite by the id 14419285155 and put in this as {_id: divcount}.
If you add the missing quotes, the query should do exactly what you want there. (edit: quotes were present in the original query, fixed the post.)
hint: db._explain() gives information about that.
Trying to reproduce, using the knows sample graph:
arangosh> var examples = require("org/arangodb/graph-examples/example-graph.js");
arangosh> var g = examples.loadGraph("knows_graph");
arangosh> db._query("FOR e IN GRAPH_TRAVERSAL('knows_graph', [{_id: 'persons/eve'}], 'inbound', {edgeCollection: 'knows'}) return e").toArray()
[
[
{
"vertex" : {
"_id" : "persons/eve",
"_rev" : "1405497100114",
"_key" : "eve",
"name" : "Eve"
}
}
]
]
However what creates a somewhat similar behaviour is to use a collection not part of the graph definition:
arangosh> db._create("othercol")
arangosh> db.othercol.save({_key: "1" })
arangosh> db._query("FOR e IN GRAPH_TRAVERSAL('knows_graph', [{_id: 'othercol/1'}], 'inbound', {edgeCollection: 'knows'}) return e").toArray()
[ ]
As pointed out in the Comments, edge relations have a direction. If you want to have edges pointing in both directions, you need to create a second relation in the other direction. Edges not fullfilling the edge definitions may be ignored.
I have a small Graph:
CREATE
(Dic1:Dictioniary { name:'Dic1' }),
(Dic2:Dictioniary { name: 'Dic2' }),
(Dic3:Dictioniary { name: 'Dic3' }),
(File1:File { name: 'File1' }),
(File2:File { name: 'File2' }),
(File3:File { name: 'File3' }),
(Dic2)-[:contains]->(Dic1),
(Dic1)-[:contains]->(File1),
(Dic3)-[:contains]->(File2),
(File1)-[:references]->(File3),
(File2)-[:references]->(File3)
I need a cypher query to find out, if for example Dic2 and Dic3 have paths/relations, where they reference the same File.
In this case it would be true; the mutual File is File3.
Thanks for your help
When you are looking for just two dictionaries you can achieve this in a single statement:
MATCH (d2:Dictioniary { name:'Dic2' }),(d3:Dictioniary { name:'Dic3' })
MATCH (d2)-[:contains|references*]->(f:File)<-[:contains|references*]-(d3)
RETURN f
It is quite expensive due to the two unbounded path matches, but it is quite cheap as it is bound from the outset by the two dictionary matches.
If you had an arbitrary number of Dictionaries to test you could do something like:
MATCH (d1:Dictioniary { name:'Dic1' }),(d2:Dictioniary { name:'Dic2' }),(d3:Dictioniary { name:'Dic3' })
WITH [d1,d2,d3] AS ds
MATCH (d)-[:contains|references*]->(f:File)
WHERE d IN ds
WITH f, ds, COLLECT(d) AS fds
WHERE length(ds)= length(fds)
RETURN f
This matches the dictionaries that you are interested in first and for each of them in turn it finds the files that they reference. Importantly the File object is preserved and the Dictionary that referenced it is collected into an array (fds). If we know that we had 3 dictionaries to begin with (length(ds)) and that a given file has the same number of related dictionaries (length(fds)) then all dictionaries must reference it.
Assuming that there may multiple paths to a given File from a given Dictionary then you can insert the DISTINCTmodifier into the second WITH statement:
WITH f, ds, COLLECT(DISTINCT(d)) AS fds