Cypher到Neo4JClient Distinct收集

Question

我正在尝试获取一个从基节点到其根节点的1行路径。Cypher查询如下所示：

start n = node:node_auto_index(Name = "user1") match path = (n-[r:IS_MEMBER_OF_GROUP*]->b) return last(collect(distinct path));

但是，当将其改为Neo4JClient语法时：

var k = clientConnection.Cypher
                .Start(new { n = "node:node_auto_index(Name = 'user1')" })
                .Match("path = (n-[r:IS_MEMBER_OF_GROUP*]->b)")
                .ReturnDistinct<Node<Principles>>("last(collect(path))").Results;

它会得到一个错误：

{"Value cannot be null.\r\nParameter name: uriString"}

从那里继续下去时：

 Neo4jClient encountered an exception while deserializing the response from the server. This is likely a bug in Neo4jClient.



Please open an issue at https://bitbucket.org/Readify/neo4jclient/issues/new



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Include the full text of this exception, including this message, the stack trace, and all of the inner exception details.



Include the full type definition of Neo4jClient.Node`1[[IQS_Neo4j_TestGraph.Nodes.Principles, IQS Neo4j TestGraph, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].



Include this raw JSON, with any sensitive values replaced with non-sensitive equivalents:



{

  "columns" : [ "last(collect(path))" ],

  "data" : [ [ {

    "start" : "http://localhost:7474/db/data/node/3907",

    "nodes" : [ "http://localhost:7474/db/data/node/3907", "http://localhost:7474/db/data/node/3906", "http://localhost:7474/db/data/node/3905", "http://localhost:7474/db/data/node/3904" ],

    "length" : 3,

    "relationships" : [ "http://localhost:7474/db/data/relationship/4761", "http://localhost:7474/db/data/relationship/4762", "http://localhost:7474/db/data/relationship/4763" ],

    "end" : "http://localhost:7474/db/data/node/3904"

  } ] ]

}

如何将密码查询转换为Neo4JClient查询？

Answer 1

您返回的是一个PathsResult，而不是一个Node<>，所以如果您将查询更改为：

 var k = clientConnection.Cypher
            .Start(new { n = "node:node_auto_index(Name = 'user1')" })
            .Match("path = (n-[r:IS_MEMBER_OF_GROUP*]->b)")
            .ReturnDistinct<PathsResult>("last(collect(path))").Results; //<-- Change here

您将得到结果，这将返回我对我的数据库运行查询所得到的结果，如果您特别希望这个帖子中的节点：获取PathsResults涵盖转换为实际节点和关系。

另一件事(这将有助于查询更好地执行，因为neo4j可以更容易地缓存执行计划)是，您可以通过以下操作更改start以使其使用参数：

.Start(new { n = Node.ByIndexLookup("node_auto_index", "Name", "user1")})