使用Cypher从Neo4j图中提取子图 [英] Extract subgraph from Neo4j graph with Cypher

问题描述

假设我在Neo4j中有5个节点的集合，这样集合中的每个节点都连接到集合中的至少一个其他节点。我想从Neo4j中提取由节点集合及其相互作用形成的子图。目前，我正在使用一种非常原始的方法，该方法涉及尝试从系统中的每个节点到每个其他节点查找匹配项：

Suppose I have a collection of 5 nodes in Neo4j, such that each node in the collection is connected to at least one other node in the collection. I want to extract the subgraph formed by the collection of nodes and their interactions from Neo4j. Currently, I'm using a really primitive method that involves attempting to find a match from each node in the system to every other node:

MATCH p=(n)-[]->(m)
WHERE id(n) IN [3,4,5,6,7] AND id(m) IN [3,4,5,6,7]
RETURN relationships(p);

但是，此查询既多余又效率低下；它必须经历集合中节点的每个排列（例如，它将与节点＃3和＃4以及ALSO＃4和＃3匹配）。有没有更有效的方式使用Cypher ONLY（无Java）获取由这些节点形成的子图？

However, this query is both redundant and inefficient; it must go through every permutation of nodes in the collection (e.g. it will match node #3 and #4, and ALSO #4 and #3). Is there any more efficient way of getting the subgraph formed by these nodes using Cypher ONLY (no Java)?

以下是我所说的子图的示例：

Here's an example of what I mean by "subgraph":

我希望Cypher返回所有以绿色标记的关系。请注意，集合中的节点不必与图表的其余部分隔离；它们仍然可以与图中的其他节点建立关系，但是我希望Cypher仅返回绿色的关系。

I want Cypher to return all the relationships marked in green. Please note that the nodes in the collection don't have to be isolated from the rest of the graph; they can still have relationships with other nodes in the graph, but I want Cypher to return only the relationships in green.

推荐答案

I要扩展Richards的答案，还可以将其限制为ID在不同组中的节点。

I want to extend on Richards answer, you can also restrict it to nodes whose id's are in separate groups.

MATCH (n) WHERE id(n) IN [3,4,5,6,7]
MATCH p=(n)-->(m) 
WHERE id(n) < id(m) AND id(m) IN [3,4,5,6,7]
RETURN relationships(p);

结果

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