In RedisGraph using Cypher/python is there a way to
Merge two nodes and move all the relationships from the old node to the new node ?
I suspect there are no pure Cypher solution... in that case what will be the equivalent atomic operations and how to combine them to achieve MERGE-nodes+rel
neo4j have apoc.refactor.mergeNodes(nodes, options), apoc.refactor.mergeRelationships(rels, options), but that doesn't help me !:( because I'm using RedisGraph.
the problem is that in RG I dont have lower level access to do enumeration/iteration to do this programmatically !!
this worked in one direction I have to apply -> the reverse <- second time.
MATCH (old)-[r:q]->(from_to)
WHERE old.val = $old
MATCH (new) WHERE new.val = $new
MERGE (new)-[nr2:q]->(from_to)
SET nr2.val = r.val
DELETE r
any way to combine it in single query ?
I think this can be accomplished in pure Cypher:
MATCH (old {val: 'old'})-[e:E]->(old_to)
MERGE (new {val: 'new'})
CREATE (new)-[e2:E]->(old_to)
SET e2.prop1 = e.prop1, [...]
DELETE e
The chief annoyance here is that all of the edge properties (and node properties, if those are also to be migrated) must be set explicitly, as RedisGraph does not currently support setting property maps.
Related
Here are some details:
NebulaGraph version is 3.2.1
Deployment way is distributed
Installation way is RPM
Disk is Non-SSD
CPU and memory information are Single node 4core8g
Specific description of the problem
I use the following nGQL to query the 2-hop path data with vid of 76517618765348
MATCH p=(v)-[e:`belong`*2]-(v2)
WHERE id(v) IN ["76517618765348"]
AND ALL(l IN e WHERE l.create_long == 1665368234) RETURN p LIMIT 100
The results are as shown in the figure below
Among them, the edge belong has the property of which type is long and name create_long. When I use the == to query the edge with a value of 1665368234 to filter. Why can’t I find the corresponding data?
The real data relationship is as shown in the figure below
Are you sure you would like to filter all edges with this WHERE clause: WHERE l.create_long == 1665368234?
MATCH p=(v)-[e:`belong`*2]-(v2)
WHERE id(v) IN ["76517618765348"]
AND ALL(l IN e WHERE l.create_long == 1665368234) RETURN p LIMIT 100
As you are using == here, I guess maybe you actually would like to express one of the edge in list of e fulfills create_long == 1665368234?
If it’s the case as I guessed, you should instead use ANY instead of ALL here:
And that is:
MATCH p=(v)-[e:`belong`*2]-(v2)
WHERE id(v) IN ["76517618765348"]
AND ANY(e_ IN e WHERE e_.create_long == 1665368234)
RETURN p LIMIT 100
I am new to gremlin.
I am facing issue in fetching the vertex and edges when sometimes edge from a vertex does not exists.
for example bellow query works fine if it gets all the vertex and edges.
but for one use case edge
`.outE("PRODUCES").`as`("produces"))`
does not exists in db.
in that case bellow query doesnt return any result.
I need your help to resolve this issue.
when edges does not exit then i want input_entity and processed_by in result.
janusGraph.traversal().V()
.has("isActive", "true")
.hasLabel("ENTITY").`as`("input_entity")
.outE("PROCESSED_BY").`as`("processed_by")
.inV().`as`("job")
.outE("PRODUCES").`as`("produces")
.select<String>("job").outE("HAS_STATE")
.`as`("job_state_edge").inV().hasLabel("JOB_STATE").`as`("job_state")
.select<String>("input_entity").outE("HAS_STATE")
.`as`("input_entity_state_edge").inV().hasLabel("ENTITY_STATE").`as`("input_entity_state")
.select<String>("input_entity").outE("CONNECTS_TO").`as`("connects_to")
.inV().hasLabel("ENTITY").has("entityName", TextP.startingWith(rootNamespace))
.`as`("output_entity").outE("HAS_STATE")
.`as`("output_entity_state_edge").inV().hasLabel("ENTITY_STATE").`as`("output_entity_state")
.select<String>("input_entity","output_entity","processed_by","produces","job","job_state","input_entity_state","output_entity_state","input_entity_state_edge","output_entity_state_edge","job_state_edge","connects_to")
.by(elementMap<Element, Any>()).toList()
with optional
janusGraph.traversal().V()
.has("isActive", "true")
.hasLabel("ENTITY").`as`("input_entity")
.outE("HAS_STATE").`as`("input_entity_state_edge").inV().hasLabel("ENTITY_STATE").`as`("input_entity_state")
.select<String>("input_entity").outE("PROCESSED_BY").`as`("processed_by")
.inV().`as`("job").outE("HAS_STATE").`as`("job_state_edge").inV().hasLabel("JOB_STATE").`as`("job_state")
.select<String>("job")
.optional(
outE("PRODUCES").`as`("produces")
.select<String>("input_entity").outE("CONNECTS_TO").`as`("connects_to")
.inV().hasLabel("ENTITY").has("entityName", TextP.startingWith(rootNamespace))
.`as`("output_entity").outE("HAS_STATE").`as`("output_entity_state_edge").inV().hasLabel("ENTITY_STATE").`as`("output_entity_state"))
.select<String>("input_entity","output_entity","processed_by","produces","job","job_state","input_entity_state","output_entity_state","input_entity_state_edge","output_entity_state_edge","job_state_edge","connects_to")
.by(elementMap<Element, Any>()).toList()
There are two Gremlin steps that can help in cases like this. When you have a part of a query that may or may not exist, but you either want the results up to that point if it does not exist or the results afterwards if it does exist, you can wrap that part of the query in an optional step.
For example :
g.V('3').optional(out())
Will either return V['3'] or the adjacent vertices if out yields results.
In cases where you want to select a value that may not exist, you can do something like this:
coalesce(select('a'),constant('No results'))
EDITED to add:
If you need to return multiple results, rather than just using select try a project('a','b,',c') type of approach where each by modulator for the project can contain its own coalesce step.
I am new to Neo4j and Cypher query.My create query is like each Shop has 2 chillers which has 2 PLCs each which in turn has 2 sensors each.
The create is as below
Create(:SHOP{name:"Shop1"})-[:hasChiller]->(:CHILLER{name:"Chiller1"})
Create(:SHOP{name:"Shop1"})-[:hasChiller]->(:CHILLER{name:"Chiller2"})
Create(:SHOP{name:"Shop2"})-[:hasChiller]->(:CHILLER{name:"Chiller3"})
Create(:SHOP{name:"Shop2"})-[:hasChiller]->(:CHILLER{name:"Chiller4"})
Create(:CHILLER{name:"Chiller1"})-[:hasPLC]->(:PLC{name:"Plc1"})
Create(:CHILLER{name:"Chiller1"})-[:hasPLC]->(:PLC{name:"Plc2"})
Create(:CHILLER{name:"Chiller2"})-[:hasPLC]->(:PLC{name:"Plc3"})
Create(:CHILLER{name:"Chiller2"})-[:hasPLC]->(:PLC{name:"Plc4"})
Create(:CHILLER{name:"Chiller3"})-[:hasPLC]->(:PLC{name:"Plc5"})
Create(:CHILLER{name:"Chiller3"})-[:hasPLC]->(:PLC{name:"Plc6"})
Create(:CHILLER{name:"Chiller4"})-[:hasPLC]->(:PLC{name:"Plc7"})
Create(:CHILLER{name:"Chiller4"})-[:hasPLC]->(:PLC{name:"Plc8"})
Create(:PLC{name:"Plc1"})-[:hasSensor]->(:SENSOR{name:"Sensor1"})
Create(:PLC{name:"Plc1"})-[:hasSensor]->(:SENSOR{name:"Sensor2"})
Create(:PLC{name:"Plc2"})-[:hasSensor]->(:SENSOR{name:"Sensor3"})
Create(:PLC{name:"Plc2"})-[:hasSensor]->(:SENSOR{name:"Sensor4"})
Create(:PLC{name:"Plc3"})-[:hasSensor]->(:SENSOR{name:"Sensor5"})
Create(:PLC{name:"Plc3"})-[:hasSensor]->(:SENSOR{name:"Sensor6"})
Create(:PLC{name:"Plc4"})-[:hasSensor]->(:SENSOR{name:"Sensor7"})
Create(:PLC{name:"Plc4"})-[:hasSensor]->(:SENSOR{name:"Sensor8"})
Create(:PLC{name:"Plc5"})-[:hasSensor]->(:SENSOR{name:"Sensor9"})
Create(:PLC{name:"Plc5"})-[:hasSensor]->(:SENSOR{name:"Sensor10"})
Create(:PLC{name:"Plc6"})-[:hasSensor]->(:SENSOR{name:"Sensor11"})
Create(:PLC{name:"Plc6"})-[:hasSensor]->(:SENSOR{name:"Sensor12"})
Create(:PLC{name:"Plc7"})-[:hasSensor]->(:SENSOR{name:"Sensor13"})
Create(:PLC{name:"Plc7"})-[:hasSensor]->(:SENSOR{name:"Sensor14"})
Create(:PLC{name:"Plc8"})-[:hasSensor]->(:SENSOR{name:"Sensor15"})
Create(:PLC{name:"Plc8"})-[:hasSensor]->(:SENSOR{name:"Sensor16"})
However the Match to get the sensors under SHOP1
MATCH(s:SHOP{name:"Shop1"})-[:hasChiller]->(cc:CHILLER)-[:hasPLC]->(pp:PLC)-[:hasSensor]->(ss:SENSOR) return ss.name
returns nothing.Says no changes and no data.
I am trying this out on Neo4J sandbox environment.I did this based on the understanding i had using match clause in SQL SERVER GRAPH 2019 where this works.
Can anyone point out where i am going wrong?
You are improperly creating multiple instances of the "same" node. You should create each node once, and then use its bound variable name later on when you need to create relationships involving that node.
Delete all your data and follow this pattern instead (you have to fill in the "..." parts):
CREATE
(sh1:SHOP{name:"Shop1"}), (sh2:SHOP{name:"Shop1"}),
(c1:CHILLER{name:"Chiller1"}), (c2:CHILLER{name:"Chiller2"}),(c3:CHILLER{name:"Chiller3"}), (c4:CHILLER{name:"Chiller4"}),
(p1:PLC{name:"Plc1"}), ..., (p8:PLC{name:"Plc8"}),
(se1:SENSOR{name:"Sensor1"}), ..., (se16:SENSOR{name:"Sensor16"}),
(sh1)-[:hasChiller]->(c1), (sh1)-[:hasChiller]->(c2),
... // create remaining relationships using bound variable names for nodes
I have a JanusGraph database with a graph structure as follows:
(Paper)<-[AuthorOf]-(Author)
I'm want to use Gremlin's match clause to query the data and assign the results to a subgraph. This is what I have so far:
g.V().match(
__.as('a').has('Paper','paperTitle', 'The name of my paper'),
__.as('a').in('AuthorOf').outV().as('b')).
select('b').values()
This query returns what I want, the Authors of the paper I'm for which I'm searching. However, I want to assign the results to a subgraph so I can export it using:
sg.io(IoCore.graphml()).writeGraph("/home/ubuntu/myresults.graphml")
Previously, I've achieved this with a different query structure like this:
sg = g.V().has('paperTitle', 'The name of my paper').
inE('AuthorOf').subgraph('sg1').
outV().
cap('sg1').
next()
Is there away to achieve the same results using the 'match()' statement?
After a little trial and error I was able to create a working solution:
sg = g.V().match(
__.as('a').has('Paper','paperTitle', 'ladle pouring guide'),
__.as('a').inE('AuthorOf').subgraph('sg').outV().as('b')).
cap('sg').next()
At first, I was trying to use the 'select' statement to isolate the subgraph. After reviewing the documentation on 'subgraph' and learning more about side-effects in gremlin I realized it wasn't necessary.
I'm trying to populate a list with a dataset and set the selected option with a helper function that compares the current data with another object's data (the 2 objects are linked)
I made the same type of list population with static variables:
Jade-
select(name='status')
option(value='Newly Acquired' selected='{{isCurrentState "Newly Acquired"}}') Newly Acquired
option(value='Currently In Use' selected='{{isCurrentState "Currently In Use"}}') Currently In Use
option(value='Not In Use' selected='{{isCurrentState "Not In Use"}}') Not In Use
option(value='In Storage' selected='{{isCurrentState "In Storage"}}') In Storage
Coffeescript-
"isCurrentState" : (state) ->
return #status == state
This uses a helper isCurrentState to match a given parameter to the same object that my other code is linked to so I know that part works
The code I'm trying to get to work is :
Jade-
select.loca(name='location')
each locations
option(value='#{siteName}' selected='{{isCurrentLocation {{siteName}} }}') #{siteName}
Coffeescript-
"isCurrentLocation": (location) ->
return #locate == location
All the other parts are functioning 100%, but the selected part is not
I've also tried changing the way I entered the selected='' part in a manner of ways such as:
selected='{{isCurrentLocation "#{siteName}" }}'
selected='{{isCurrentLocation "#{siteName} }}'
selected='{{isCurrentLocation {{siteName}} }}'
selected='#{isCurrentLocation "{{siteName}}" }'
selected='#{isCurrentLocation {{siteName}} }'
selected='#{isCurrentLocation #{siteName} }'
Is what I'm trying to do even possible?
Is there a better way of achieving this?
Any help would be greatly appreciated
UPDATE:
Thanks #david-weldon for the quick reply, i've tried this out a bit and realised that I wasn't exactly clear in what I was trying to accomplish in my question.
I have a template "update_building" created with a parameter( a buidling object) with a number of attributes, one of which is "locate".
Locations is another object with a number of attributes as well, one of which is "siteName". One of the siteName == locate and thus i need to pass in the siteName from locations to match it to the current building's locate attribute
Though it doesn't work in the context I want to use it definitely pointed me in a direction I didn't think of. I am looking into moving the parent template(The building) date context as a parameter into the locations template and using it from within the locations template. This is easily fixable in normal HTML spacebars with:
{{>locations parentDataContext/variable}}
Something like that in jade would easily solve this
Short answer
selected='{{isCurrentLocation siteName}}'
Long answer
You don't really need to pass the current location because the helper should know it's own context. Here's a simple (tested) example:
jade
template(name='myTemplate')
select.location(name='location')
each locations
option(value=this selected=isCurrentLocation) #{this}
coffee
LOCATIONS = [
'Newly Acquired'
'Currently In Use'
'Not In Use'
'In Storage'
]
Template.myTemplate.helpers
locations: LOCATIONS
isCurrentLocation: ->
#toString() is Template.instance().location.get()
Template.myTemplate.onCreated ->
#location = new ReactiveVar LOCATIONS[1]
I looked into the datacontexts some more and ended up making the options that populate the select into a different template and giving that template a helper, accessing the template's parent's data context and using that to determine which location the building had saved in it so that I could set that option to selected
Jade-
template(name="location_building_option")
option(value='#{siteName}' selected='{{isSelected}}') #{siteName}
Coffeescript -
Template.location_building_option.helpers
'isSelected': ->
parent = Template.parentData(1)
buildSite = parent.locate
return #siteName == buildSite
Thanks #david-weldon, Your answer helped me immensely to head in the right direction