CODEWITHSUNDEEP
neo4jcypher
Mihai Raulea
Mihai Raulea

Reputation: 438

Cypher - multiple relationships with same label, i want to delete just one

I have the following schema: (Node a and b are identified by id and are the same in both relationships)

(a)-[r:RelType {comment:'a comment'} ]-(b)
(a)-[r:RelType {comment:'another comment'} ]-(b)

So i have 2 nodes, and an arbitrary number of relationships between them. I want to delete just one of the relationships, and i don t care which one. How can i do this?

I have tried this, but it does not work:

match (a {id:'aaa'})-[r:RelType]-(b {id:'bbb'}) where count(r)=1 delete r;

Any ideas?

Here is the real-world query:

match (order:Order {id:'order1'}),(produs:Product {id:'supa'}),
(order)-[r:ordprod {status:'altered'}]->(produs) with r limit 1 set r.status='alteredAgain'
return (r);

The problem is Chypher says Set 1 property, returned 1 row in 219 ms , but when i inspect the database, it turns out all relationships have been updated.

Upvotes: 2

Views: 679

Answers (3)

Sumeet Sharma
Sumeet Sharma

Reputation: 2583

Hope this helps(As per my understanding you are trying to modify a relationship between two given nodes)

MATCH (order:Order {id:'order1'})-[r:ordprod {status:'altered'}]->(produs:Product {id:'supa'})
WITH order,r,produs 
LIMIT 1 
DELETE r
WITH order,produs
CREATE (order:Order {id:'order1'})-[r:ordprod {status:'alteredAgain'}]->(produs:Product {id:'supa'})
return (r);

And the reason for all your relationships getting updated is that after your WITH clause you are passing only r ie the relationship which may be same between all such nodes of label Order and Product. So when you do r.status = 'alteredagain' it changes all the relationships instead of changing between those two specific nodes that you matched in the beginning of your cypher query. Pass them too in the WITH and it will work fine!

Upvotes: 0

ShreyansS
ShreyansS

Reputation: 167

I tried to implement data structure like your's (Mihai's). and gone with both solutions; i.e., Stefan's and Sumit's. Stefan's solution is working at my side. Mihai, are you still facing any problems?

Upvotes: 0

Stefan Armbruster
Stefan Armbruster

Reputation: 39915

Use the following:

match (a {id:'aaa'})-[r:RelType]-(b {id:'bbb'}) 
with r
limit 1
delete r

Upvotes: 3

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