CODEWITHSUNDEEP
neo4jcypher
AJN
AJN

Reputation: 1206

neo4j merge 2 or multiple duplicate nodes

I am feeding my neo4j db manually using cypher, so prone to error like creating duplicate nodes:

The duplicate nodes will have each relationships to other nodes. Is there a built-in function to merge these nodes? Or should I do it manually?

Sounds possible, but complicated with cypher script:

Upvotes: 6

Views: 6022

Answers (3)

Alexandr Alexandrovich
Alexandr Alexandrovich

Reputation: 11

I think you can try:

apoc.refactor.mergeNodes(nodes, options)

For relations:

apoc.refactor.mergeRelationships(rels, options)

Or:

apoc.periodic.iterate(query, options)

Upvotes: 1

Michael Hunger
Michael Hunger

Reputation: 41676

Try this:

MATCH (n:MyNode),(m:MyNode),(o:OtherNode {id:123})
WHERE n <> m
MATCH (m)-[r:FOO]->()
CREATE (n)-[r2:FOO]->(o)
SET r2 = r
DELETE r,m

Upvotes: 1

fbiville
fbiville

Reputation: 8950

To avoid this situation in the future, please look at the MERGE keyword in Cypher. Unfortunately, as far as I know, there is nothing in Cypher (yet) like:

MATCH (n:MyNode),(m:MyNode)
WHERE ID(n) <> ID(m) AND
PROPS(n) IN PROPS(m) AND PROPS(m) IN PROPS(n)
(...) DELETE (...)

The fictional function PROPS of the third line is not part of Cypher language and User-Defined functions have not made it yet into Neo4j.

If you're not working with production instances, the easiest is probably to back up your data folder and try to start the insertion over (with MERGE).

Otherwise, you can also try writing a traversal to collect the duplicates and delete them in batch (here is an example with the REST API).

Upvotes: 2

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