I'm using py2neo in Python to run my Cypher queries.
I'm trying to create Person nodes and relationships between then.
My DataFrame is like this:
df
>>> id_user name follows.profiles
a_123 Mc Marcão <3 [a_134, a_934, a_145, a_988]
a_234 john a_111
a_934 alice NaN
: : :
: : :
So here we can see that a Person can follows multiple persons, because follows.profiles is a list.
So this is what I did:
for index, row in df.iterrows():
graph.run('''
UNWIND $label3 as follow_profile
MERGE (p1:Profile { id_user: $label1, name: $label2 })
MERGE (p1)-[:FOLLOWS]->(p2:Profile { id_user: follow_profile })
''', parameters = {'label1': row['id_user'],
'label2': row['name'],
'label3': row['follows.profiles']
})
So the nodes are created and their relationships too.
Now I want to set labels to the nodes relateds. How can I do this?
All the nodes you created already have a Profile label. But the neo4j Browser does not show the labels since normally you want identifying information to display for each node. However, the Browser does allow you to specify a different color for each label.
See the documentation for how to do that.
Related
I am loading simple csv data into neo4j. The data is simple as follows :-
uniqueId compound value category
ACT12_M_609 mesulfen 21 carbon
ACT12_M_609 MNAF 23 carbon
ACT12_M_609 nifluridide 20 suphate
ACT12_M_609 sulfur 23 carbon
I am loading the data from the URL using the following query -
LOAD CSV WITH HEADERS
FROM "url"
AS row
MERGE( t: Transaction { transactionId: row.uniqueId })
MERGE(c:Compound {name: row.compound})
MERGE (t)-[r:CONTAINS]->(c)
ON CREATE SET c.category= row.category
ON CREATE SET r.price =row.value
Next I do the aggregation to count total orders for a compound and create property for a node in the following way -
MATCH (c:Compound) <-[:CONTAINS]- (t:Transaction)
with c.name as name, count( distinct t.transactionId) as ord
set c.orders = ord
So far so good. I can accomplish what I want but I have the following 2 questions -
How can I create the orders property for compound node in the first step itself? .i.e. when I am loading the data I would like to perform the aggregation straight away.
For a compound node I am also setting the property for category. Theoretically, it can also be modelled as category -contains-> compound by creating Categorynode. But what advantage will I have if I do it? Because I can execute the queries and get the expected output without creating this additional node.
Thank you for your answer.
I don't think that's possible, LOAD CSV goes over one row at a time, so at row 1, it doesn't know how many more rows will follow.
I guess you could create virtual nodes and relationships, aggregate those and then use those to create the real nodes, but that would be way more complicated. Virtual Nodes/Rels
That depends on the questions/queries you want to ask.
A graph database is optimised for following relationships, so if you often do a query where the category is a criteria (e.g. MATCH (c: Category {category_id: 12})-[r]-(:Compound) ), it might be more performant to create a label for it.
If you just want to get the category in the results (e.g. RETURN compound.category), then it's fine as a property.
I failed to create relationships in Neo4J and I would like to encourage anyone who has sucessfully done it to help me.
The desired result is to have a detailed visualisation of who is a brother to whom, who is who's mother and so on. I want to extract the data from single parent-child relationships. That means, setting a relationship like [:relatedTo {:how['daughter']}] if a node has a parent whose name corresponds to the field node.name and the gender of the node is F.
I have my CSV file that looks like this.
1;Jakub Hančin;M;1994;4;3
2;Hana Hančinová;F;1991;4;3
3;Alojz Hančin jr.;M;1968;15;14
4;Viera Hančinová;F;1968;9;
5;Miroslav Barus sr.;M;1965;9;
6;Helena Barusová;F;1942;;
7;Miroslav Barus jr.;M;1995;6;5
8;Martin Barus;M;1991;6;5
9;Hedviga Barusová;F;1945;;
10;Peter Hančin jr.;M;1991;12;13
11;Zuzka Hančinová;F;1996;12;13
12;Andrea Hančinová;F;1966;;
13;Peter Hančin sr.;M;1965;15;14
14;Alojz Hančin sr.;M;1937;;
15;Anna Hančinová;F;1945;;
This is my personal family tree and I would like to visualize it through Neo4J.
It is a file created with Excel, where I put the information into a table and create a database. Then it was converted to .csv file which is importable into Neo4J. I have sucessfully installed it and now I am at the point of writing the Cypher script to manage it. So far, I have this:
LOAD CSV WITH HEADERS FROM "file:c:/users/Skelo/Desktop/Family Database/Family Database CSV UTF.txt" AS row FIELDTERMINATOR ';'
CREATE (n:Person)
SET n = row, n.name = row.name,
n.personID = toInt(row.personID) , n.G = row.G,
n.Year = toInt(row.Year), n.Parent1 = row.Parent1, n.Parent2 = row.Parent2
WITH n
MATCH(n:Person),(b:Person)
WHERE n.Parent1 = b.name OR n.Parent2 = b.name
CASE b.gender
WHEN b.gender = 'F' THEN
CREATE (b)-[:isRelatedTo{how:['mother']}]->(n)
WHEN b.gender = 'M' THEN
CREATE (b)-[:isRelatedTo{how:['father']}]->(n)
RETURN *
The error message shown looks like this.
Invalid input 'A': expected 'r/R' (line 11, column 2 (offset: 389))
"CASE b.gender"
^
Somehow, I can't figure out why this does not work. Why can't I use the Case command? The Neo4J does not allow me to use anything but the command CREATE (it expects a letter R after C and not an A, this means the CREATE command).
Again, I want to do this. I have a few nodes that are correctly set. For each of those nodes (they represent people), I want to look into the Parent1 and Parent2 fields and to look for a node that has the same name as one of these fields. If it matches one of these, I want to mark that node as a father or a mother to the previous node (judging by the gender of the node, which represents the person).
This way I would like to fill the graph database with many relationships, but I fail at this very basic step. Please help me. If you can, please do not only say what is wrong and why it is wrong, but present a solution that works.
Since you want to create the isRelatedTo relationship regardless of gender and only the property is dependent upon a conditional, do this:
CREATE (b)-[r:isRelatedTo]->(n)
SET r.how = CASE b.gender WHEN 'F' THEN 'mother' ELSE 'father' END
I need to create a python function such that it adds nodes and relationship to a graph and returns the number of created nodes and relationships.
I have added the nodes and relationship using graph.cypher.execute().
arr_len = len(dic_st[story_id]['PER'])
for j in dic_st[story_id]['PER']:
graph.cypher.execute("MERGE (n:PER {name:{name}})",name = j[0].upper()) #creating the nodes of PER in the story
print j[0]
for j in range(0,arr_len):
for k in range(j+1,arr_len):
graph.cypher.execute("MATCH (p1:PER {name:{name1}}), (p2:PER {name:{name2}}) WHERE upper(p1.name)<>upper(p2.name) CREATE UNIQUE (p1)-[r:in_same_doc {st_id:{st_id}}]-(p2)", name1=dic_st[story_id]['PER'][j][0].upper(),name2=dic_st[story_id]['PER'][k][0].upper(),st_id=story_id) #linking the edges for PER nodes
What I need is to return the number of new nodes and relationships created.
What I get to know from the neo4j documentation is that there is something called "ON CREATE" and "ON MATCH" for MERGE in cypher, but thats not being very useful.
The browser interface for neo4j do actually shows the number of nodes and relationship updated. This is what I need to return, but I am not getting quite the way for it to access it.
Any help please.
In case you need the exact counts of properties either created or updated then you have use "Match" with "Create" or "Match" with "Set" and then count the size of results. Merge may not return which ones are updated and which ones are created.
When you post your query against the Cypher endpoint of the neo4j REST API without using py2neo, you can include the argument "includeStats": true in your post request to get the node/relationship statistics. See this question for an example.
As far as I can tell, py2neo currently does not support additional parameters for the Cypher query (even though it is using the same API endpoints under the hood).
In Python, you could do something like this (using the requests and json packages):
import requests
import json
payload = {
"statements": [{
"statement": "CREATE (t:Test) RETURN t",
"includeStats": True
}]
}
r = requests.post('http://your_server_host:7474/db/data/transaction/commit',
data=json.dumps(payload))
print(r.text)
The response will include statistics about the number of nodes created etc.
{
"stats":{
"contains_updates":true,
"nodes_created":1,
"nodes_deleted":0,
"properties_set":1,
"relationships_created":0,
"relationship_deleted":0,
"labels_added":1,
"labels_removed":0,
"indexes_added":0,
"indexes_removed":0,
"constraints_added":0,
"constraints_removed":0
}
}
After executing your query using x = session.run(...) you can use x.summary.counters to get the statistics noted in Martin Perusse's answer. See the documentation here.
In older versions the counters are available as a "private" field under x._summary.counters.
I apologize now for my bad English. I'm Italian
I'm just using Neo4j for the thesis, but I still have doubts about the multi use.
1) I have created from the web interface, two nodes. I realized that Neo4j has given these indices 0 and 1 (for research). Now suppose that I was wrong and I have to delete the node with index 1 .. Once deleted do I create a new one and the system puts index 2.
Practically now the first node with index 0 and the second node with index 2 But I want the second node still has index 1 (basically I want to use the index of the first, as I do?)
2) The same problem with the relationship between two nodes. if I'm wrong to create it, the gate and I create another, I lose the index of the one deleted.
3) If I have to create a relationship between 2 nodes with the double arrow, as I do.
I saw that every arrow must have a label, so if I create a relationship between 1 and 2, and a relationship between 2 and 1, you get the double arrow, but with two labels and does not suit me. Thank you for your help
sorry for my very bad English
You should really try to use your own IDs or unique identifier for your nodes, then you can disregard the internal node IDs all together.
If you begin with this Cypher statement in a new database (you only have to set it once),
CREATE CONSTRAINT ON (node:MyNodeLabel) ASSERT node.myid IS UNIQUE
then you can create nodes and relationship like this,
CREATE (a:MyNodeLabel { myid : 0 })
CREATE (b:MyNodeLabel { myid : 1 })
CREATE (a)-[r:RELTYPE]->(b)
or if you do not write the create statements in the same transaction,
CREATE (:MyNodeLabel { myid : 2 })
CREATE (:MyNodeLabel { myid : 3 })
then later,
MATCH (a:MyNodeLabel { myid : 2 }), (b:MyNodeLabel { myid : 3 })
CREATE (a)-[r:RELTYPE]->(b)
or create two nodes and a relationship at the same time
MERGE (:MyNodeLabel { myid : 4 })-[r:RELTYPE]->(:MyNodeLabel { myid : 5 })
You can of course change MyNodeLabel and myid to any identifier you like.
The problem you have with the relationship labels is purely visual or do I misunderstand you?
You know that you can traverse relationships in any direction so maybe you do not need two relationships?
Here is the documentation for Cypher if you have missed it, http://docs.neo4j.org/chunked/stable/.
ok. sorry. I return at home today.... Another question. when you create a relationship with a label on the arrow. how do sometime in the future to change the label
without delete the relationship? is possible?
Q ok. sorry. I return at home today.... Another question. when you create a relationship with a label on the arrow. how do sometime in the future to change the label without delete the relationship? is possible?
ANS Yes,
You can do that easily you can server for the node and remove label only from the node it will not impact the relation ship , but i will suggest you to assing another one if that was the only label on the node so you can group it properly.
match(n:User{Id:1})
remove n:User set n:DeletedUser
return n
Here's the situation:
I have a node that has a property ContactId which is set as unique and indexed. The node label is :Contact
(node:Contact {ContactId:1})
I have another node similar to that pattern for Address:
(node2:Address {AddressId:1})
I now try to add a new node that (among other properties, includes ContactId (for referencing))
(node3:ContactAddress {AddressId:1,ContactId:1})
When I run a merge command for each, the time for adding a node that contains a property that is set as unique in another node type seems to make the process much slower.
The ContactAddress node only contains relational properties between the Contact and Address nodes. Contact and Address nodes contain up to 10 properties each. Is this a bug, where Neo4j is check the property key -> value -> then node label?
Code and screenshot below:
string strForEach = string.Format("(n in {{{0}}} |
MERGE (c:{1} {{{2} : n.{2}}}) SET c = n)", propKey, label, PK_Field);
var query = client
.Cypher
.ForEach(strForEach)
.WithParam(propKey, entities.ToList());
Constraint checks are more expensive than just inserts. They also take a global lock on the constraint to prevent multiple insertion.
I saw you don't use parameters, but string substitiution, I really recommend to change that and go with parameters.
Also setting the whole node c to n triggers constraint check again.
Your probably want to use the ON CREATE SET clause of MERGE
(n in {nodes} |
MERGE (c:Label {key : n.key}}) ON CREATE SET c.foo = n.foo, c.bar = n.bar )