如何使用Neo4jClient在C＃.Net中的neo4j现有节点和新节点之间创建关系？

Question

我正在使用Neo4j数据库进行C＃.net项目，并且无法使用C＃.Net在Neo4j中的现有节点和新节点之间创建关系。

我正在使用以下代码创建节点

// Create entities
var refA = client.Create(new Person() { FName = "Person A" });
var refB = client.Create(new Person() { FName = "Person B" });
var refC = client.Create(new Person() { FName = "Person C" });
var refD = client.Create(new Person() { FName = "Person D" });

// Create relationships
client.CreateRelationship(refA, new KnowsRelationship(refB));
client.CreateRelationship(refB, new KnowsRelationship(refC));
client.CreateRelationship(refB, new HatesRelationship(refD, new HatesData("Crazy guy")));
client.CreateRelationship(refC, new HatesRelationship(refD, new HatesData("Don't know why...")));

现在，我想使用某种条件从数据库中获取现有节点之一与创建新节点之间的关系。 但是不能这样做

Answer 1

如果您想使用C＃中的Neo4J，您仍然需要对Cypher有深入的了解。

您可以在这里找到有关它的非常文档：

密码查询语言-文档

我创建了一个示例程序，供您创建3个节点以及它们之间的2个关系，然后查询与节点1相邻的节点。

using Neo4jClient;
using Neo4jClient.Cypher;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Neo4JTest
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                GraphClient client = new GraphClient(new Uri("http://localhost:7474/db/data"));
                client.Connect();

                // Create nodes and relationship
                MyNode node1 = new MyNode() { Name = "Test 1" };
                MyNode node2 = new MyNode() { Name = "Test 2" };

                NodeReference<MyNode> node1ref = client.Create<MyNode>(node1);
                NodeReference<MyNode> node2ref = client.Create<MyNode>(node2);

                MyRelationShip rel12 = new MyRelationShip(node2ref);

                var Rel1 = client.CreateRelationship<MyNode, MyRelationShip>(node1ref, rel12);               

                MyNode node3 = new MyNode() { Name = "Test 3" };
                NodeReference<MyNode> node3ref = client.Create<MyNode>(node3);

                MyRelationShip rel13 = new MyRelationShip(node3ref);
                var Rel13 = client.CreateRelationship<MyNode, MyRelationShip>(node1ref, rel13);

                var query = client.Cypher.Start(new { n1 = node1ref })
                                        .Match("n1-[:MYRELATIONSHIP]->targetnode")
                                        .Return<MyNode>(targetnode => targetnode.As<MyNode>());
                var res = query.Results;

                int i = 0;
                foreach (MyNode n in res)
                {
                    i++;
                    Console.WriteLine(i + ". Name: '" + n.Name + "'");
                }
            }
            catch(NeoException ex)
            {
                Console.WriteLine(ex.ToString());
            }
            Console.ReadKey();
        }


        class MyNode
        {
            private string _name = "";

            public string Name
            {
                get
                {
                    return _name;
                }

                set
                {
                    _name = value;
                }
            }
        }
        public class MyRelationShip : Relationship, IRelationshipAllowingSourceNode<MyNode>, IRelationshipAllowingTargetNode<MyNode>
        {
            public static readonly string TypeKey = "MYRELATIONSHIP";

            public MyRelationShip(NodeReference targetNode)
                : base(targetNode)
            { }

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