I have created a nice graph using Neo4j Desktop, using a local CSV file that I added to the project. now I'm trying to use python to do that automatically for that I'm trying to use methods from here https://py2neo.org/2021.1/bulk/index.html like create/merge nodes/relatioships.
I have 2 questions,
Do I need to use create method (create node for exmaple) and after that to use merge method (merge nodes for this example) or can use merge nodes from the begining?
I have tried to use merge only and I got some wierd things when I'm using large sample size.
2)After creation of nodes and relationships how can I change the visualization of the nodes (put some value in the node)?
*If there is an other way to use python to create graph from a big CSV file I would like to hear, Thanks!
Related
I am trying to simulate a file system using Neo4j, Cypher, and Python(Py2Neo).
I have created the data model as shown in the following screenshot.
Type=0 means folder and type=1 means file.
.
.
I am implementing functions like Copy, Move etc for files/folders.
Move functions look simple, I can create a new relationship and delete the old one. But copying files/folders need to copy the sub-graph.
How can I copy the sub-graph?
I am creating a python module so trying to avoid apoc.
Even though you're trying to avoid APOC, it already has this feature implemented in the most recent release: apoc.refactor.cloneSubgraph()
For a non-APOC approach you'll need to accomplish the following:
MATCH to distinct nodes and relationships that make up the subgraph you want to clone. Having a separate list for each will make this easier to process.
Clone the nodes, and get a way to map from the original node to the cloned node.
Process the relationships, finding the start and end nodes, and following the mapping to the cloned nodes, then create the same relationship type using the cloned nodes for your start and end nodes of the relationship, then copy properties from the original relationship. This way you don't have any relationships to the originals, just the clones.
Determine which nodes you want to reanchor (you probably don't want to clone the original), and for any relationship that goes to/from this node, create it (via step 3) to the node you want to use as the new anchor (for example, the new :File which should be the parent of the cloned directory tree).
All this is tough to do in Cypher (steps 3 and 4 in particular), thus the reason all this was encapsulated in apoc.refactor.cloneSubgraph().
I have already created the nodes before and I would like to use the relationships file used some time ago during a batch- import, to create relationships using the load CSV method.
This is my relationships CSV file:
You'll need to use LOAD CSV for this (USING PERIODIC COMMIT), although you'll need to watch out for spaces in both the headers (if you use them) and your fields. trim() may help in your fields.
The headers shouldn't have : in them if at all possible.
The biggest obstacle will be dynamically using the type of the relationship from the csv. Currently Cypher does not deal with relationship types dynamically, you'll need an alternate approach. Install APOC Procedures and use apoc.create.relationship() to handle that.
I have created graph using MERGE to avoid repetition, following is the query
LOAD CSV WITH HEADERS
FROM "file:///C:/Users/username/Desktop/file.csv"
AS network
MERGE (sourceNode {id:network.node1})
MERGE (destNode {id:network.node2})
WITH sourceNode,
destNode,
network
It doesn't assign labels to nodes but I need labels to query graph. Is there any way to assign labels to nodes?
Thanks in advance.
You seemed to miss the variables which are supposed to be assigned to a node before the labels.This way your nodes will be assigned labels and you can use their respective variables for operations on them. I've modified the query. Hope this helps!
LOAD CSV WITH HEADERS
FROM "file:///C:/Users/username/Desktop/file.csv"
AS network
MERGE (n:sourceNode {id:network.node1})
MERGE (m:destNode {id:network.node2})
WITH n,m,network
You may want to review the developer guide. Here's how to create a node with a label. However, if you want to set a label dynamically, such as from a CSV, then you will need to use APOC Procedures for this, as it is not supported natively by Cypher.
I am new to Neo4j and I want to add a new node to an existing relationship using Structr platform.
This is the Cypher query that I tested in Neo4j web browser and it works.
match(projects:Project {name:'IRIS Recognition Java'})
create(client:Client {name:'Andreas Pal'}) CREATE(projects)-[w:IS_PART_OF]->(client)
return w
In the Structr platform I created a table that contains all the existing projects from database and I want to assign a member to the project.
I tried to put in a table date a query to bring also the clients. And I don't know how to create the assign. Any help would be very much appreciated. Thank you.
You need to use Structr's means of editing the data in the database. If you use Cypher directly, you are modifying the data on a different (wrong) level. You can either use Structr directly to create relationships, or you have to make the relationships in a way that Structr can detect and "see" those relationships.
Please have a look at https:/support.structr.com/article/295 for more information.
Using Neo4j's Batch Import Tool, how can I create multiple nodes from a single row, and then attribute some properties to Node 1 and some to Node 2?
This is an example from 29.3:
movieId:ID,title,year:int,:LABEL
tt0133093,"The Matrix",1999,Movie
tt0234215,"The Matrix Reloaded",2003,Movie;Sequel
tt0242653,"The Matrix Revolutions",2003,Movie;Sequel
Is there a way to make it so title is "movieId.title" and year is its own ID? Then I can abstract that out to multiple nodes.
The import tool (in contrast to LOAD CSV) expects exactly one node per line. So you have to use some preprocessing to make the format fitting your desired graph model.
Typical candidates for this a csvkit or the usual suspects from a unix command line: sed, awk, ...
In your case I'd strip out the title into a separate file for creating the :Title nodes, and create another csv file for the relationships between movies and titles.
You can re-use the same csv file but use two different header files, with different columns used as :ID and columns you don't want for this node as :IGNORED
As the header is independent from the data you can use that approach to pull in the same file several times for different nodes, relationships, etc.
It's also explained here: http://neo4j.com/developer/guide-import-csv/#_super_fast_batch_importer_for_huge_datasets