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Questions tagged [neo4j]

Neo4j is an open-source graph database (GDB) well suited to connected data. Please mention your exact version of Neo4j when asking questions. You can use it for recommendation engines, fraud detection, graph-based search, network ops/security, and many other user cases. The database is accessed via official drivers in Java, JavaScript, Python and .NET, or community-contributed drivers in PHP, Ruby, R, Golang, Elixir, Swift and more.

Neo4j is a open-source, transactional, high-performance native graph database.

Neo4j stores its data as a graph: Nodes are connected through Relationships, both with arbitrary properties. Neo4j features a graph-centric declarative query language called Cypher. Its drivers support many programming languages. More details in the Online Training and the Neo4j Manual.

Neo4j offers a fully-managed cloud database (Database as a service) called Neo4j AuraDB.

For questions that are not suitable for the Stack Overflow Q&A Format, please reach out on Discord. Neo4j also maintains a public Feedback Board for feature ideas and future development directions.

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22696 questions
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Concurrent query and delete, leads to Memory Leak in Neo4j 2.0.3 community

This program simulates a server that concurrently queries nodes based on user input and deletes them. Each user request (of query and then delete) is being processed on a separate thread. There are no compile or runtime issues however, a Memory Leak…
Debajyoti Roy
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Neo4j Cypher Query to aggregate count of connecting nodes

I have an email graph model located here: http://console.neo4j.org/r/go164n I am trying to find the count of messages being sent from one email address to another and vice versa. Basically, there are several email address nodes along with message…
user2819872
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Neo4j Relationship Naming Conventions for Similar Actions in Cypher

I am aware of the absence of a constraint for naming relationships, though it is tough to get one guideline and work with it over all the relationships that we might encounter. Would you go with something like…
mulkave
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Cypher match path based on previous relationship

I am trying to impose restrictions on my path match pattern. I would like to match the next relationship based on the type of the previous used relationship. Here is an example of a simplified Database: (A)-1-(B)-2-(C)-1-(E)-2-(F) | …
N_2
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Get property of neo4j node with optional relationship like left join

I am having 2 nodes lets say of 2 type 'Student' and 'Class' Student have {id, name}. Class have {id, name}. Student can have optional relationship with Class node as 'ATTENDS'. (s:Student)-[r:ATTENDS]->(c:Class). [r:ATTENDS] - Optional…
Somnath Muluk
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Neo4j Finding path but without a certain node

I am not very familiar with Neo4j because I just used it for several days. But now I want to find path between two nodes like path :　A & D A -> B -> C -> D A -> B -> E -> D A -> C -> E -> D and using "WHERE NOT" to eliminate Node B so I will leave…
darrelltw
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Make part of a Cypher query dynamic with spring data neo4j 3

I have a UserRepository class that extends GraphRepository: public interface UserRepository extends GraphRepository { @Query("MATCH (User:_User) WHERE User.network = {0} RETURN User") Iterable executeFilterTest(String…
lulu88
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Starting first node in Heo4j HA cluster fails even when allowed to create cluster

Whilst trying to diagnose a different issue with my cluster I tried isolating my environments to force elections events. When starting nodes in isolation though my app failed to start with this exception: Caused by:…
JohnMark13
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Delete leaf nodes with single relationship in neo4j

I am trying to remove leaf nodes in Neo4j, but only those with a single incoming relationship. (I'm so close.) I have a query that returns the exact node I wish to remove. However, when I replace the RETURN with DELETE, it removes more than the…
SteveS
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Levenshtein distance and modern indexes in Neo4j

I have been using legacy indexes (aka Lucene) to run queries like the following in Neo4j Cypher in order to go through millions of simhashes in realtime and find similar items: START file = node:File("simhash:THE_SIMHASH_HERE~0.8") RETURN…
retrography
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create unique and merge slow

I'm playing with a neo4j database consisting of ~ 275,000 English words linked to the letters they contain. Am running Neo4j 2.0.1 Community Edition on Windows. Am trying to use the following Cypher to insert new word nodes into the graph, update…
jeffj4a
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Working with indexes in neo4j and py2neo

I have just started working with py2neo and neo4j. I am confused about how to go about using indices in my database. I have created a create_user function: g = neo4j.GraphDatabaseService() users_index = g.get_or_create_index(neo4j.Node, "Users") def…
Vaibhav Aggarwal
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Bad performance compared to MySql with Neo4j

I migrated a MySQL database to Neo4j and tested a simple request. I was very surprised to see that an equivalent request was 10 to 100 times longer in neo4j than in MySql. I'm working on Neo4j 2.0.1. In the original MySql schema I have the three…
Benito de la casita
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Neo4j MERGE relationships with properties

I'm Neo4j noob and I'm trying to create unique relationship between two nodes depending on relationship properties. Let's say we have node A and node B. I would like to create a new relationship R between A and B, if R.since = 1 or R.since IS NULL.…
Ilya
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Using Neo4j in Grails without the Grails neo4j-plugin and GORM

Is it possible to use Grails to provide Controllers and Views, Neo4j as the database and (self written) domain classes that wrap the database access and CRUD operations without the neo4j plugin? The data I have (~10^6 Nodes, 10^7 Relationships) are…
Hobbes-Calvin
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