In order to store hierarchical data, can a graph database (Neo4j) be viewed as an alternative to JCR based solutions (ModeShape, JackRabbit)? Or do they belong to 2 different level of abstraction meaning that a JCR implementation could use Neo4j under the hood?
Thank you for your help.
Both, people are building CMS applications with Neo4j as storage backend (see http://structr.org)
A JCR implementation could also be done using Neo4j, some people worked on that in the past, we also have a group using Neo4j as backend storage for Apache Shindig.
You also might want to take a look at OrientDB (http://www.orientdb.org/) which combines features of a Graph-DB (as Neo4j) with those of a Document-DB. There even seems to be a prototype implementation using OrientDB as a storage-adapter for Jackrabbit (https://github.com/eiswind/jackrabbit-orient) that illustrates the implementation of such a hybrid approach.
Related
We currently use gremlin.net library in a net core 3.0 application to connect to Azure Cosmos db. We would like to connect to neo4j.
Can we use same gremlin.net library for neo4j? Assuming gremlin
server is installed.
Will Neo4j.Driver library support gremlin
queries? What exact library to use?
Any code sample to connect and
create a node in neo4j using gremlin library for a .net core 3.0
application?
Is neo4j really a better graph model than Azure cosmos?
Can we use same gremlin.net library for neo4j? Assuming gremlin server is installed.
Yes, assuming you mean Gremlin.Net and yes, Gremlin Server should be installed hosting neo4j.
Will Neo4j.Driver library support gremlin queries? What exact library to use?
I don't think that's possible. Neo4j drivers will support Cypher based queries, not Gremlin.
Any code sample to connect and create a node in neo4j using gremlin library for a .net core 3.0 application?
The beauty of Gremlin is that the code examples for one graph database are the same for any other and for the most part, Gremlin in Java is the same as Gremlin in .NET or any other programming language (aside from changes that make Gremlin more ergonomic to the programming language itself). So, if you want to create a node then it's always going to be:
using static Gremlin.Net.Process.Traversal.AnonymousTraversalSource;
var g = Traversal().WithRemote(
new DriverRemoteConnection(new GremlinClient(new GremlinServer("localhost", 8182))));
g.AddV("person").Property("name","Bob").Iterate();
Is neo4j really a better graph model than Azure cosmos?
My personal opinion is that you try them both and determine which is better for yourself given you requirements. That is the choice that Apache TinkerPop and Gremlin help to give you in that you can try lots and lots of different graph systems out there to find the one best suited to your needs.
as I was wandering in the Web looking for a Gremlin implementation for Neo4j I found these two possible solutions:
https://github.com/thinkaurelius/neo4j-gremlin-plugin
http://tinkerpop.incubator.apache.org/docs/3.0.2-incubating/#neo4j-gremlin
Does anybody know what is the difference between the two in practice?
I saw that 1. is a Neo4j plugin while it's not really clear to me what the second is, and if it would lock the entire database thus not allowing other connections (I noticed that it requires the path to the data folder).
Which one is preferred in the neo4j community?
Cheers,
Alberto
I'm not sure there's really a difference as there isn't a direct comparison to be made. The second link is to the TinkerPop project and specifically to the Neo4j implementation of TinkerPop APIs. It runs in an embedded mode and does not yet have support for HA (though we hope to have that soon). The Neo4j implementation can be run in Gremlin Server which let's you send Gremlin to it as a REST, websockets, etc endpoint.
The project in the first link you provided uses that implementation to allow you to send Gremlin to Neo4j Server - so the first project depends on the second.
Your rule of thumb should be activity in the source code.
neo4j-gremlin-plugin has 3 commits this year - https://github.com/thinkaurelius/neo4j-gremlin-plugin/commits/master
tikerpop is much more active - https://github.com/apache/incubator-tinkerpop/commits/master/neo4j-gremlin/src/main/java/org/apache/tinkerpop/gremlin/neo4j
neo4j-gremlin-plugin
Extending existing Neo4j server with support for Gremlin Query Language.
TinkerPop Neo4j-Gremlin
Extending Gremlin console with support for Neo4j server.
I'm working on a project (a social network) which use Neo4j (v1.9) as the underlying datastore and Spring Data Neo4j.
I'm trying to add a tag system to the project and I'm searching for ways to efficiently implement tag recommendation using collaborative filtering strategies.
After a lot of researches, I've come with these options:
Cypher. It is the embedded query language used by Neo4j. No other framework needed, maybe the computational times are better than the others. Maybe I can easily implement the queries using Spring Data Neo4j.
Apache Mahout. It offers machine learning algorithms focused primarly in the areas of collaborative filtering, clustering and classification. However, it isn't designed for graph databases and could be potentially slow.
Apache Giraph. Open source counterpart of Google Pregel.
Apache Spark. It is a fast and general engine for large-scale data processing.
reco4j. It is the best suited solution until now, but the project seems dead.
Apache Spark GraphX + Mazerunner. Suggested by the answer of #johnymontana. I'm documenting on it. The main issue is that I don't know if it supports collaborative filtering.
Graphaware Reco. Suggested by #ChristopheWillemsen in a comment. From the official site
is an extensible high-performance recommendation engine skeleton for
Neo4j, allowing for computing and serving real-time as well as
pre-computed recommendations.
However, I haven't understand yet if it works with old version of Neo4j (I can't upgrade the Neo4j version at the moment).
So, what do you suggest and why? Feel free to suggest other interesting frameworks not listed above.
Cypher is very fast when it comes to local traversals, but is not optimized for global graph operations. If you want to do something like compute similarity metrics between all pairs of users then using a graph processing framework (like Apache Spark GraphX) would be better. There is a project called Mazerunner that connects Neo4j and Spark that you might want to take a look at.
For a pure Cypher approach, here and here are a couple of recent blog posts demonstrating Cypher queries for recommendations.
I am considering Neo4J for some project. I recall reading somewhere that multi-document ACID transactions are only supported for embedded database, but not for the standalone one. Searching at the Neo4J site, I could not find any info about this. Some more information about this, or some pointers could help. Thank you.
Neo4j itself supports now transactions over the wire with 2.0
See: http://docs.neo4j.org/chunked/milestone/rest-api-transactional.html
Spring Data Neo4j does not yet and it will take a while until we get there, as it means to rewrite the core to use cypher throughout which it doesn't do now.
I understand there are many advantages in using Spring data neo4j's advanced mapping rather than the simple mapping.
My question is what are the cons of using advanced mapping over the simple mapping?
I feel that there are almost no drawbacks of using the advanced mode. The only thing that's been bugging me, is the relatively poor IDE support of AspectJ. This was initially a hell to configure and get it right. Apart from that, our application is a lot faster with the advanced mapping mode so we never looked back.
According to Q5 in this post, simple mapping is favoured if you are talking to Neo4J via REST style while advanced mapping if you are using Neo4J embedded