How to delete multiple nodes, (NOT ALL) in neo4j?
I have this queryMATCH (n)
where n.name IS NULL
delete n
It returns more than one node, I want to delete all those nodes(All nodes, which are mistakenly created thats why become null).
The error, I am facing is
javax.transaction.HeuristicRollbackException: Failed to commit transaction Transaction(11, owner:"qtp16626756-84")[STATUS_NO_TRANSACTION,Resources=1], transaction rolled back ---> javax.transaction.xa.XAException
CASE 2: What to do in case of NOT NULL (property) but no any relationship is associated within a node or two; means a node which is kind of orhpan, not connected with other node.
I tried to use LIMIT/SKIP but not working.Any help?
You need to also delete any relationships connected to those nodes, like so:
match (n)
where n.name IS NULL
optional match (n)-[r]-()
delete n, r
Update for your second case (this deletes only orphans):
match (n)
where NOT (n)--()
and n.name IS NULL
delete n
Related
I want to delete all nodes and relationships.
I run MATCH ()-[r]-() DELETE r to delete all the relationships.
Then, I run MATCH (n) DELETE n to delete all the nodes. It does delete all the nodes, but the problem is that it also gives me this error:
Neo.DatabaseError.Transaction.TransactionCommitFailed
Unable to complete transaction.
How do I delete all nodes and relationships with getting this error?
To delete all nodes and all relationships, I do DETACH DELETE
Reference:
https://neo4j.com/docs/cypher-manual/current/clauses/delete/#delete-delete-all-nodes-and-relationships
MATCH (n)
DETACH DELETE n;
If nothing works, then rename (or remove) your neo4j data folder and restart your server.
<HOME_NEO4j>/data/data/transactions/neo4j
It looks like your database is hitting an OOM Exception.
As stated in Large Delete Transaction Best Practices in Neo4j
If you need to delete some large number of objects from the graph, one needs to be mindful of the not building up such a large single transaction such that a Java OUT OF HEAP Error will be encountered.
Delete all constraints and indexes
CALL apoc.schema.assert({},{},true);
Batch delete with CALL {} IN TRANSACTIONS syntax or apoc.periodic.iterate:
MATCH (n:Foo) where n.foo='bar'
CALL { WITH n
DETACH DELETE n
} IN TRANSACTIONS OF 10000 ROWS;
OR
CALL apoc.periodic.iterate(
"MATCH (n) RETURN n",
"DETACH DELETE n",
{batchSize:10000, parallel:false})
I want to Delete this Pessoa node and its relations to others,
but I don't want to delete the other nodes.
This node has a Guid ID property with value c40f314f-0ecf-42e1-b44d-85b6d72f134a
I tried
MATCH (n {ID: 'c40f314f-0ecf-42e1-b44d-85b6d72f134a'}) DELETE n;
But this ERROR appears:
Neo.ClientError.Schema.ConstraintValidationFailed: Cannot delete node<35>, because it still has relationships. To delete this node, you must first delete its relationships.
Using
MATCH (n {ID: 'c40f314f-0ecf-42e1-b44d-85b6d72f134a'}) DETACH DELETE n;
Deleted 1 node, deleted 2 relationships, completed after 2 ms.
Note that relationships of the node were removed as well.
According to this post I tried to map all related entities in a list.
I used the same query into the post with a condition to return a list of User but it returns duplicate object
MATCH (user:User) WHERE <complex conditions>
WITH user, calculatedValue
MATCH p=(user)-[r*0..1]-() RETURN user, calculatedValue, nodes(p), rels(p)
Is it a bug? I'm using SDN 4.2.4.RELEASE with neo4j 3.2.1
Not a bug.
Keep in mind a MATCH in Neo4j will find all occurrences of a given pattern. Let's look at your last MATCH:
MATCH p=(user)-[r*0..1]-()
Because you have a variable match of *0..1, this will always return at least one row with just the user itself (with rels(p) empty and nodes(p) containing only the user), and then you'll get a row for every connected node (user will always be present on that row, and in the nodes(p) collection, along with the other connected node).
In the end, when you have a single user node and n directly connected nodes, you will get n + 1 rows. You can run the query in the Neo4j browser, looking at the table results, to confirm.
A better match might be something like:
...
OPTIONAL MATCH (user)-[r]-(b)
RETURN user, calculatedValue, collect(r) as rels, collect(b) as connectedNodes
Because we aggregate on all relationships and connected nodes (rather than just the relationships and nodes for each path), you'll get a single row result per user node.
In SQL:
Delete From Person Where ID = 1;
In Cypher, what's the script to delete a node by ID?
(Edited: ID = Neo4j's internal Node ID)
Assuming you're referring to Neo4j's internal node id:
MATCH (p:Person) where ID(p)=1
OPTIONAL MATCH (p)-[r]-() //drops p's relations
DELETE r,p
If you're referring to your own property 'id' on the node:
MATCH (p:Person {id:1})
OPTIONAL MATCH (p)-[r]-() //drops p's relations
DELETE r,p
The cleanest sweep for a node with id "x" is
MATCH (n) where id(n) = x
DETACH DELETE n
https://neo4j.com/docs/cypher-manual/current/clauses/delete/#delete-delete-a-node-with-all-its-relationships
https://neo4j.com/docs/cypher-manual/current/functions/scalar/#functions-id
Old question and answered, but to delete node when it has relationships, use DETACH
MATCH (n) where ID(n)=<your_id>
DETACH DELETE n
or otherwise you get this:
Neo.ClientError.Schema.ConstraintValidationFailed: Cannot delete node<21>, because it still has relationships. To delete this node, you must first delete its relationships.
It's like SQL's CASCADE
When the node is a orphan.
Start n=node(1)
Delete n;
Following the link provided by #saad-khan, here's an example for getting the nodes and relationships ids.
The code below shows the ids, so you can make sure that you're deleting everything related to the given ID.
MATCH (node)-[relation:HAS]->(value)
where ID(node)=1234
RETURN ID(instance), ID(value), ID(r)
Ps.: ":HAS" is an example of an relationship.
I am trying to delete a whole subgraph, using the following query:
match
(n:StartNode {id:'id1'})-[r*1..6]-(m)
foreach(rel in r|delete rel) with n, collect(distinct m) as del_nodes2
foreach(node in del_nodes2|delete node);
All components in the subgraph are connected. The start node does exist. The maximum chain length is 6. However, i am getting the following error:
javax.transaction.HeuristicRollbackException: Failed to commit transaction Transaction(6, owner:"qtp1905632138-213")[STATUS_NO_TRANSACTION,Resources=1], transaction rolled back ---> javax.transaction.xa.XAException
2 suggestions:
Specify relationship directionality in your MATCH clause, or else you could end up deleting not just the descendants of your start node, but all its ancestors as well! Also, this may be why your deletion is failing -- some of the ancestor nodes may have other relationships that your query does not try to delete.
You should be able to simplify you query.
Try this:
MATCH (:StartNode {id:'id1'})-[r*1..6]->(m)
FOREACH(rel in r | DELETE rel)
DELETE m;