I'm running the following cypher code. It used to work perfectly on previous versions of neo4j. Now it's not setting the attributes. The CSV file is intact and do possess the following fields. In the shell it's not even showing the line number on the last two rows, it's like it's completely ignoring the command.
using periodic commit
load csv with headers from "file:/relacionamento.csv" as row
match (p1:Pessoa {idpessoa: toint(row.idpessoa1)})
match (p2:Pessoa {idpessoa: toint(row.idpessoa2)})
create (p1)-[r:RELACIONAMENTO]->(p2) set r.peso_relacionamento = tofloat(row.peso_relacionamento),
r.peso_relacionamento_ponderado = tofloat(row.peso_relacionamento_fator)
Related
I've got two csv files Job (30,000 entries) and Cat (30 entries) imported into neo4j and am trying to create a relationship between them
Each Job has a cat_ID and Cat contains the category name and ID
after executing the following
LOAD CSV WITH HEADERS FROM 'file:///DimCategory.csv' AS row
MATCH (job:Job {cat_ID: row.cat_ID})
MATCH (cat:category {category: row.category})
CREATE (job)-[r:under]->(cat)
it returns (no changes, no records)
I received a prompt recommending that I index the category and so using
Create INDEX ON :Job(cat_id); I did, but I still get the same error
How do I create a relationship between the two?
I am able to get this to work on a smaller dataset
You are probably trying to match on non-existing nodes. Try
LOAD CSV WITH HEADERS FROM 'file:///DimCategory.csv' AS row
MERGE (job:Job {cat_ID: row.cat_ID})
MERGE (cat:category {category: row.category})
CREATE (job)-[r:under]->(cat)
Have a look in your logs and see if you are running out of memory.
You could try chunking the data set up into smaller pieces with Periodic Commit and see if that helps:
:auto USING PERIODIC COMMIT 1000
LOAD CSV WITH HEADERS FROM 'file:///DimCategory.csv' AS row
MATCH (job:Job {cat_ID: row.cat_ID})
MATCH (cat:category {category: row.category})
CREATE (job)-[r:under]->(cat)
I'm using cypher and the neo4j browser to create nodes from csv input.
I want to read in each row of my csv file with headers and then create a node with that row as properties.
MY current code is:
LOAD CSV WITH HEADERS FROM '<yourFilePath>' AS ROW
WITH ROW
CREATE (n:node $ROW)
This throws an error saying parameter missing.
Try this
LOAD CSV WITH HEADERS FROM '<yourFilePath>' AS row
CREATE (n:node)
SET n+= row
In Cypher, variables that start with "$" must be passed to the query as parameters. Your Cypher code is locally binding values to the ROW variable (and not passing a parameter), so change $ROW to ROW.
In addition, if you want to make sure that you do not generate duplicate nodes, you should consider using MERGE instead of CREATE. But before you do so, you must carefully read the documentation on MERGE to understand how to use it properly.
I am importing the following to Neo4J:
categories.csv
CategoryName1
CategoryName2
CategoryName3
...
categories_relations.csv
category_parent category_child
CategoryName3 CategoryName10
CategoryName32 CategoryName41
...
Basically, categories_relations.csv shows parent-child relationships between the categories from categories.csv.
I imported the first csv file with the following query which went well and pretty quickly:
USING PERIODIC COMMIT
LOAD CSV FROM 'file:///categories.csv' as line
CREATE (:Category {name:line[0]})
Then I imported the second csv file with:
USING PERIODIC COMMIT
LOAD CSV FROM 'file:///categories_relations.csv' as line
MATCH (a:Category),(b:Category)
WHERE a.name = line[0] AND b.name = line[1]
CREATE (a)-[r:ISPARENTOF]->(b)
I have about 2 million nodes.
I tried executing the 2nd query and it is taking quite long. Can I make the query execute more quickly?
Confirm you are matching on right property. You are setting only one property for Category node i.e. name while creating
categories. But you are matching on property id in your second
query to create the relationships between categories.
For executing the 2nd query faster you can add an index on the property (here id) which you are matching Category nodes on.
CREATE INDEX ON :Category(id)
If it still takes time, You can refer my answer to Load CSV here
Assume a Node "Properties". I am using "LOAD CSV with headers..."
Following is the sample file format:
fields
a=100,b=110,c=120,d=500
How do I convert fields column to having a node with a,b,c,d and 100,110,120,500 respectively as the properties of the node "Properties"?
LOAD CSV WITH HEADERS FROM 'file:/sample.tsv' AS row FIELDTERMINATOR '\t'
CREATE (:Properties {props: row.fields})
The above does not create individual properties, but sets a string value to props as "a=100,b=110,c=120,d=500"
Also, different rows could have different set of Key values. That is the key needs to be dynamic. (There are other columns as well, I trimmed it for SO)
fields
a=100,b=110,c=120,d=500
X=300,y=210,Z=420,P=600
...
I am looking for a way to not split this key-value as columns and then load. The reason is they are dynamic - today it is a,b,c,d it may change to aa,bb,cc,dd etc.
I don't want to keep on changing my loader script to recognize new column headers.
Any pointers to solve this? I am using the latest 3.0.1 neo4j version.
First things first: Your file format currently defines a single header/property: fields:
fields
a=100,b=110,c=120,d=500
Since you defined a tab as field terminator, that entire string (a=100,b=110,c=120,d=500) would end up in your node's props property:
To have properties loaded dynamically: First set up proper header:
"a","b","x","y"
1,2,,
,,3,4
Then you can query with something like this:
LOAD CSV WITH HEADERS FROM 'file:///Users/David/overflow.csv' AS row
CREATE (:StackOverflow { a:row.a, b:row.b,x:row.x,y:row.y})
Then when you run something like:
match(so:StackOverflow) return so
You'll get the variable properties you wanted:
I'm new to Neo4J, and I want to try it on some data I've exported from MySQL. I've got the community edition running with neo4j console, and I'm entering commands using the neo4j-shell command line client.
I have 2 CSV files, that I use to create 2 types of node, as follows:
USING PERIODIC COMMIT
LOAD CSV WITH HEADERS FROM "file:/tmp/updates.csv" AS row
CREATE (:Update {update_id: row.id, update_type: row.update_type, customer_name: row.customer_name, .... });
CREATE INDEX ON :Update(update_id);
USING PERIODIC COMMIT
LOAD CSV WITH HEADERS FROM "file:/tmp/facts.csv" AS row
CREATE (:Fact {update_id: row.update_id, status: row.status, ..... });
CREATE INDEX ON :Fact(update_id);
This gives me approx 650,000 Update nodes, and 21,000,000 Fact nodes.
Once the indexes are online, I try to create relationships between the nodes, as follows:
MATCH (a:Update)
WITH a
MATCH (b:Fact{update_id:a.update_id})
CREATE (b)-[:FROM]->(a)
This fails with an OutOfMemoryError. I believe this is because Neo4J does not commit the transaction until it completes, keeping it in memory.
What can I do to prevent this? I have read about USING PERIODIC COMMIT but it appears this is only useful when reading the CSV, as it doesn't work in my case:
neo4j-sh (?)$ USING PERIODIC COMMIT
> MATCH (a:Update)
> WITH a
> MATCH (b:Fact{update_id:a.update_id})
> CREATE (b)-[:FROM]->(a);
QueryExecutionKernelException: Invalid input 'M': expected whitespace, comment, an integer or LoadCSVQuery (line 2, column 1 (offset: 22))
"MATCH (a:Update)"
^
Is it possible to create relationships in this way, between large numbers of existing nodes, or do I need to take a different approach?
The Out of Memory Exception is normal as it will try to commit it all at once and as you didn't provide it, I assume java heap settings are set as default (512m).
You can however, batch the process with kind of pagination, only I would prefer to use MERGE rather than CREATE in this case :
MATCH (a:Update)
WITH a
SKIP 0
LIMIT 50000
MATCH (b:Fact{update_id:a.update_id})
MERGE (b)-[:FROM]->(a)
Modify SKIP and LIMIT after each batch until your reach 650k update nodes.