Creating relationships between nodes with WHERE clause and using ID in Neo4j - neo4j

I have two nodes named Room(4) and Houses(4). They have been created in the following way:
CREATE (n:Room { code: 1})
CREATE (n:Room { code: 1})
CREATE (n:Room { code: 1})
CREATE (n:Room { code: 1})
CREATE (n:House { code: 1})
CREATE (n:House { code: 2})
CREATE (n:House { code: 3})
CREATE (n:House { code: 4})
These are some of the relations that i am trying to create between the nodes
MATCH (room:Room), (house:House{code:1})
WHERE id(room) = 40
CREATE UNIQUE (room)-[:PLACED_IN]->(house) ;
MATCH (room:Room), (house:House{code:2})
WHERE id(room) = 41
CREATE UNIQUE (room)-[:PLACED_IN]->(house) ;
MATCH (room:Room), (house:House{code:3})
WHERE id(room) = 42
CREATE UNIQUE (room)-[:PLACED_IN]->(house) ;
The ID's have not been defined before so it should be creating new rooms based on ID's or should i add the ID's manually while creating as currently the relationships are not being created due to WHERE clause?

Change your query to:
// match room by internal id
MATCH (room:Room)
WHERE id(room) = 40
// merge will create a relationship between `room.id = 40`
// and `house.code = 1`. If `house.code = 1` does not exists, it will be created
MERGE (room)-[:PLACED_IN]->(:House {code:1}) ;
MATCH (room:Room)
WHERE id(room) = 41
MERGE (room)-[:PLACED_IN]->(:House {code:2}) ;
MATCH (room:Room)
WHERE id(room) = 42
MERGE (room)-[:PLACED_IN]->(:House {code:3}) ;
Some tips:
Avoid depending on Neo4j internal IDs because the are not safe. Neo4j
reuses these IDs when nodes and relationships are deleted.
CREATE UNIQUE is deprecated. Use MERGE instead.

Related

Updating node attributes based on new nodes

I have edges like this:
(People)-[:USE]->(Product)
(People)-[:REVIEW]->(Product)
Now I have a new csv of People who are reviewers but they are missing some of the attributes I have already.
I want to do something like:
LOAD CSV WITH HEADERS FROM "file:///abcd.csv" AS row
MERGE (svc:Consumer {name: row.referring_name})
ON CREATE SET
svc.skewNum = toInteger(row.skew_num)
MERGE (p:PrimaryConsumer) WHERE p.name = svc.name
ON MATCH SET
svc.city = p.city,
svc.latitude = toFloat(p.latitude),
svc.longitude = toFloat(p.longitude),
svc.consumerId = toInteger(p.primaryConsumerId)
Which borks:
Neo.ClientError.Statement.SyntaxError: Invalid input 'H': expected 'i/I' (line 10, column 28 (offset: 346))
"MERGE (p:PrimaryConsumer) WHERE p.name = svc.name"
I am 100% assured that the names are unique and will match a unique consumer name in the existing set of nodes (to be seen).
How would I add existing attributes to new data when I have a match on unique node attributes? (I am hoping to get unique id's, but I have to be able to perform an update to the new data on match)
Thank you.
This is the entire cypher script -- modified as per #cypher's input.
USING PERIODIC COMMIT
LOAD CSV WITH HEADERS FROM "file:///abcde.csv" AS row
MERGE (svc:Consumer {name: row.referring_name})
ON CREATE SET
svc.skeyNum = toInteger(row.skew_num)
MATCH (p:primaryConsumer {name: svc:name})
ON MATCH SET
svc.city = p.city,
svc.latitude = toFloat(p.latitude),
svc.longitude = toFloat(p.longitude),
svc.providerId = toInteger(p.providerId)
MERGE (spec:Product {name: row.svc_prod_name})
ON CREATE SET
spec.name = row.svc_prov_name,
spec.skew = toInteger(row.skew_id),
spec.city = row.svc_prov_city,
spec.totalAllowed = toFloat(row.total_allowed)
MERGE (svc)-[r:CONFIRMED_PURCHASE]->(spec)
ON MATCH SET r.totalAllowed = r.totalAllowed + spec.totalAllowed
ON CREATE SET r.totalAllowed = spec.totalAllowed
;
MERGE does not accept a WHERE clause.
Change this:
MERGE (p:PrimaryConsumer) WHERE p.name = svc.name
to this:
MERGE (p:PrimaryConsumer {name: svc.name})
[EDIT]
You entire query should then look like this:
LOAD CSV WITH HEADERS FROM "file:///abcd.csv" AS row
MERGE (svc:Consumer {name: row.referring_name})
ON CREATE SET
svc.skewNum = toInteger(row.skew_num)
MERGE (p:PrimaryConsumer {name: svc.name})
ON MATCH SET
svc.city = p.city,
svc.latitude = toFloat(p.latitude),
svc.longitude = toFloat(p.longitude),
svc.consumerId = toInteger(p.primaryConsumerId)

Neo4J - Optimizing 3 merge queries into a single query

I am trying to make a Cypher query which makes 2 nodes and adds a relationship between them.
For adding a node I'm checking if the node is existing or not, if existing then I'm simply going ahead and setting a property.
// Query 1 for creating or updating node 1
MERGE (Kunal:PERSON)
ON CREATE SET
Kunal.name = 'Kunal',
Kunal.type = 'Person',
Kunal.created = timestamp()
ON MATCH SET
Kunal.lastUpdated = timestamp()
RETURN Kunal
// Query 2 for creating or updating node 2
MERGE (Bangalore: LOC)
ON CREATE SET
Bangalore.name = 'Bangalore',
Bangalore.type = 'Location',
Bangalore.created = timestamp()
ON MATCH SET
Bangalore.lastUpdated = timestamp()
RETURN Bangalore
Likewise I am checking if a relationship exists between the above created nodes, if not exists then creating it else updating its properties.
// Query 3 for creating relation or updating it.
MERGE (Kunal: PERSON { name: 'Kunal', type: 'Person' })
MERGE (Bangalore: LOC { name: 'Bangalore', type: 'Location' })
MERGE (Kunal)-[r:LIVES_IN]->(Bangalore)
ON CREATE SET
r.duration = 36
ON MATCH SET
r.duration = r.duration + 1
RETURN *
The problem is these are 3 separate queries which will have 3 database calls when I run it via the Python driver. Is there a way to optimize these queries into a single query.
Of course you can concatenate your three queries to one.
In this case you can omit the first and second MERGE of your last query, because it is assured by the start of new query already.
MERGE (kunal:PERSON {name: ‘Kunal'})
ON CREATE SET
kunal.type = 'Person',
kunal.created = timestamp()
ON MATCH SET
kunal.lastUpdated = timestamp()
MERGE (bangalore:LOC {name: 'Bangalore'})
ON CREATE SET
bangalore.type = 'Location',
bangalore.created = timestamp()
ON MATCH SET
bangalore.lastUpdated = timestamp()
MERGE (kunal)-[r:LIVES_IN]->(bangalore)
ON CREATE SET
r.duration = 36
ON MATCH SET
r.duration = r.duration + 1
RETURN *

neo4j sum up values

I'm trying to get Total(Sum) of a property of "df" object.I have attached screen shot of sample database I'm using
I tried to get the graph using following query
MATCH P= (n:Org)-[:O_CH*0..]->()-[:LEAF*0..]->()-[:CH*0..]->()-[:FOR*0..]->() RETURN P
To create objects
create(n:Org{name:'Root',id:1})
create(n:Org{name:'L1.1',id:2,parent:1})
create(n:Org{name:'L1.2',id:3,parent:1})
create(n:Org{name:'L1.3',id:4,parent:1})
create(n:Org{name:'L2.1',id:5,parent:3})
create(n:Org{name:'L2.2',id:6,parent:4})
create(n:Op{name:'CH1',id:7,orgId:5})
create(n:Op{name:'CH2',id:8,orgId:5 ,parent:'CH1'})
create(n:Proj{name:'P1',id:9,opp:'CH2'})
create(n:Proj{name:'P2',id:10,opp:'CH1'})
create(n:R{name:'R1',id:200,orgId:2 })
create (n:df{id:100,map:8,forecast:toFloat(10)})
create (n:df{id:101,map:7,forecast:toFloat(10)})
create (n:df{id:102,map:9,forecast:toFloat(10)})
create (n:df{id:103,map:10,forecast:toFloat(10)})
create (n:df{id:104,map:200,forecast:toFloat(10)})
To Crate relationships
MATCH (c:Org),(p:Org) WHERE c.parent = p.id create (p)-[:O_CH]->(c)
MATCH (c:Op),(p:Op) WHERE c.parent = p.name create (p)-[:CH]->(c)
MATCH (c:Op),(p:Org) WHERE c.orgId = p.id create (p)-[:LEAF]->(c)
MATCH (c:Proj),(p:Op) WHERE c.opp = p.name create (p)-[:CH]->(c)
MATCH (c:R),(p:Org) WHERE c.orgId = p.id create (p)-[:LEAF]->(c)
MATCH (c:df),(p:) WHERE c.map = p.id create (p)-[:FOR]->(c)
I'm expecting 60 as total where I get 260 as total. Please let me know where I'm wrong . Need your help to figure out.
I'm trying to get Total(Sum) of a property of "df" object.
I believe you needs a simple query that match all nodes with label :df and return the sum of node.forecast. Try it:
// Match all nodes with :df label
MATCH(n:df)
// Return the sum of the property 'forecast' of each matched node
RETURN sum(n.forecast)
From comments:
Thank you Bruno.But the thing i need to get the aggregated value as a
example if i select L2.1 , i need to get the sum of df objects which
are under that node
This should work:
MATCH({name:'L2.1'})-[*]->(n)
RETURN SUM(n.forecast)

How to add unique data to a neo4j graph database

I am adding iteratively data to my neo4j database but I am stuck with how to overwrite or update existing data and to check whether the data does not already exist in there.
Basically I have a set of movies with their corresponding id's, e.g.:
[
{id: 'gameofthrones', genre: 'fantasy', release: '2017'},
{id: 'inception', genre: 'scifi', release: '2010'},
...
]
I can add the movies as follows:
CREATE
(m1:Movie {id: 'gameofthrones', genre: 'fantasy', release: '2017'}),
(m2:Movie {id: 'inception', genre: 'scifi', release: '2010'})
However, when I run the script two times, then it creates 4 nodes instead of keeping it at two nodes.
So my question is, how can I make sure that it checks whether the node id is already present, and if so overwrite it instead of creating a new node?
I tried (but only the properties get added)
// data
attributes['id'] = 'gameofthrones';
attributes['genre'] = 'fantasy';
...
// query
MERGE ( s:Movie {attributes}.id)
ON CREATE SET ( s:Movie {attributes} )
which I call in NodeJS as follows:
executeQuery(queryStr, {"attributes": attributes})
// cypher (nodejs)
function executeQuery(queryStr, params) {
var qq = Q.defer();
db.cypher({
query: queryStr,
params: params,
}, function (error, results) {
if (error) {
qq.reject(error);
} else {
if (results.length != 0) {
qq.resolve(true);
} else {
qq.resolve(false);
}
};
});
return qq.promise;
};
you must change your query to this
MERGE ( s:Movie {attributes}.id)
ON CREATE SET s += {attributes}
ON MATCH SET s += {attributes} // optional
this should work, but you should use apoc.map.clean() so you do not set the id twice, which can cause some problems.
MERGE ( s:Movie {attributes}.id)
ON CREATE SET s += apoc.map.clean({attributes},['id'],[])
You can achieve this with MERGE clause as follows
MERGE (m1:Movie {id: 'gameofthrones'})
ON CREATE SET m1.genre = 'fantasy', m1.release = '2017'
MERGE (m2:Movie {id: 'inception'})
ON CREATE SET m2.genre: 'scifi', m2.release = '2010'
Ideally you want to create queries with parameters instead of literal strings. You can achieve this if you user apoc.load.json
with "file:///home/sample.json" as url // can be also http://url/sample.json
CALL apoc.load.json(url) yield value
UNWIND value as item
MERGE (m1:Movie {id: item.id})
ON CREATE SET m1.genre = item.genre, m1.release = item.release
example for dynamic properties with apoc functions:
with "file:///home/sample.json" as url // can be also http://url/sample.json
CALL apoc.load.json(url) yield value
UNWIND value as item
MERGE (m1:Movie {id: item.id})
ON CREATE SET m1 += apoc.map.clean(item,['id'],[])
or if you do not have apoc plugin:
with "file:///home/sample.json" as url // can be also http://url/sample.json
CALL apoc.load.json(url) yield value
UNWIND value as item
MERGE (m1:Movie {id: item.id})
ON CREATE SET m1 += item
note that id will first be merged and later updated with ON CREATE SET and you want to avoid writing a single property twice, using apoc and above query we can achieve that

Neo4J deep duplicated nodes

For the data (below), my query looks like that:
MATCH p = (ob:Obiect)<--(w:Word { value:'game' })-[*]-(x) RETURN {id: id(x), value: x.value}
CREATE (w0:Obiect { value : 'Obiect' })
CREATE (w1:Word { value:'game' })
CREATE (w2:Word { value:'unreal' })
CREATE (w3:Word { value:'a' })
CREATE (w4:Word { value:'b'})
CREATE (w5:Word { value:'c' })
CREATE (w6:Word { value:'d'})
CREATE (w1)-[:IS]->(w0)
CREATE (w2)-[:IS]->(w1)
CREATE (w3)-[:HAS]->(w2)
CREATE (w4)-[:HAS]->(w3)
CREATE (w5)-[:HAS]->(w4)
CREATE (w6)-[:HAS]->(w5)
CREATE (w6)-[:HAS]->(w3)
If the relation (value:d)-->(value:a) doesn't exist then it’s okay and my results looks like this:
id 4070 value unreal
id 4071 value a
id 4072 value b
id 4073 value c
id 4074 value d
but if the relation exists then i have duplicates nodes (below). The question is how to avoid this problem?
id 4063 value unreal
id 4064 value a
id 4065 value b
id 4066 value c
id 4067 value d
id 4064 value a
id 4067 value d
id 4066 value c
id 4065 value b
id 4064 value a
You can use the MERGE clause : http://docs.neo4j.org/chunked/stable/query-merge.html
MERGE (w3:Word { value:'a' })
MERGE (w4:Word { value:'b'})
MERGE(w3)-[:HAS]->(w4)
MERGE acts as "MATCH or CREATE" .
Be aware that MERGE will attempt to match the entire pattern, which can be confusing the first times, so I recommend you this helpful article from Graphaware : http://graphaware.com/neo4j/2014/07/31/cypher-merge-explained.html

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