Neo4jClient Create and Update a Relationship

Question

I have a Neo4j Graphdatabase with access via the Neo4jClient. (It is a .NET client for the REST api of Neo4j)

There is the beginning of a documentation.

What I have done

The connection to the database works.

Client = new GraphClient(new Uri("http://localhost:7474/db/data"));
Client.Connect();

This way I can insert Nodes...

Client.Create(new myNodeClass { name = "Nobody" });

... and query them.

Node<myNodeClass> Node = Client.Get<WordNode>(138);
return Node.Data.name;

What I want to do

I simply want to add and update relationships between Nodes. (The type of relationship have to be numeric.)

Unfortunately there is no documentation about relationships yet.

There is a command named CreateRelationship. But I can't get it work.

Client.CreateRelationship(Neo4jClient.NodeReference<TSourceNode>, TRelationship);

Can you give me an example of adding and updating (numeric) relationships?

Answer 1

you could have a look at the tests, http://hg.readify.net/neo4jclient/src/4693da483a90/Test/RelationshipTests.cs or contact the author on the Neo4j mailing list, groups.google.com/group/neo4j ?

Answer 2

There's a lot to be found in the test cases... Such as this:

http://hg.readify.net/neo4jclient/src/4693da483a90/Test/ApiUsageIdeas.cs

Answer 3

I was stuck too then I realized I needed to specify the type parameter of the source node reference parameter in the CreateRelationship method.

In this example, I have created the relationship. I have not yet updated the relationship.

Disclosure(It works on my machine as a console application running visual studio 2012, YMMV)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using Neo4jClient;

namespace Neo4jClientExample
{

    class MyConsoleProgram
    {

        private GraphClient Client {get;set; }

        static void Main(string[] args)
        {

        try{
            GraphClient client = new GraphClient(new Uri("http://localhost:7474/db/data"));
            client.Connect();

            Us us = new Us { Name = "We are Us" };
            NodeReference<Us> usRef = client.Create(us);
            Console.WriteLine("us node.id: {0}", usRef.Id);

            var queryUs = client.Cypher.Start("n", "node(" + usRef.Id + ")").Return<Node<Us>>("n");
            Console.WriteLine("Us node name: {0}\n", queryUs.Results.AsEnumerable<Node<Us>>().First().Data);


            AllYourBase allYourBase = new AllYourBase { Name = "We are all your base" };
            NodeReference<AllYourBase> allYourBaseRef = client.Create(allYourBase);
            Console.WriteLine("AllYourBase node.id: {0}",allYourBaseRef.Id);

            var queryAllYourBase = client.Cypher.Start("n", "node(" + allYourBaseRef.Id + ")").Return<Node<AllYourBase>>("n");
            Console.WriteLine("AllYourBase node name: {0}\n", queryAllYourBase.Results.AsEnumerable<Node<AllYourBase>>().First().Data);

            RelationshipReference areBelongToRef = client.CreateRelationship(allYourBaseRef, new AreBelongTo(usRef));

            var query = client.Cypher.Start("allyourbase", "node(" + allYourBaseRef.Id + ")").Match("allyourbase-[:ARE_BELONG_TO]->us").Return<Node<AllYourBase>>("allyourbase");
            query.ExecuteWithoutResults();
            Console.WriteLine("Result of querying for all your base that belongs to us: {0}", query.Results.AsEnumerable<Node<AllYourBase>>().First().Data.Name);
        }
        catch(Exception ex)
        {
            Console.WriteLine("{0}", ex.Message);
            Console.WriteLine("{0}", ex.InnerException);
        }
        Console.ReadKey();
    }
}

public class Us
{
    public string Name {get; set;}

    public Us()
    {
    }
}

public class AllYourBase
{
    public string Name { get; set; }

    public AllYourBase()
    {
    }
}
public class AreBelongTo : Relationship, IRelationshipAllowingSourceNode<AllYourBase>,
                                         IRelationshipAllowingTargetNode<Us>
{
    public AreBelongTo(NodeReference targetNode)
        : base(targetNode)
    {}

    public const string TypeKey = "ARE_BELONG_TO";

    public override string RelationshipTypeKey
    {
        get { return TypeKey; }
    }
}