编写Cypher查询以创建随机节点之间的链接 [英] Write a Cypher query to CREATE links between random nodes

问题描述

要播种数据库，我想创建一小组Person节点...

To seed a database, I would like to create a small set of Person nodes...

WITH ["Amy","Bob","Cal","Dan","Eve"]
AS names
FOREACH (r IN range(0, size(names)-1) |
  CREATE (:Person {name: names[r]})
)

...，我想为每个人创建一个随机连接.可以在单个查询中做到这一点吗?

... and I would like to create a random connection for each Person. Is it possible to do this in a single query?

我想我需要将每个新的Person添加到集合中，并使用从FLOOR(RAND()* size(names))创建的变量进行工作，但是官方文档并未提供有关如何处理的许多线索.做到这一点.

I imagine that I would need to add each new Person to a collection, and work with a variable created from FLOOR(RAND() * size(names)), but the official documentation does not give many clues as to how to do this.

推荐答案

好问题！

几件事，首先，我经常更喜欢UNWIND而不是FOREACH，尤其是在这样的情况下:

A couple of things, first I often prefer UNWIND over FOREACH, particularly in a case like this:

WITH ["Amy","Bob","Cal","Dan","Eve"] AS names
UNWIND names AS name
CREATE (:Person {name: name})

就建立随机关系而言，迈克尔·汉格(Michael Hunger)撰写了一篇不错的博客文章:

As far as creating random relationships, Michael Hunger has a good blog post covering it:

http://jexp.de/blog/2014/03/quickly-create-a-100k-neo4j-graph-data-model-with-cypher-only/

在您的情况下，它将类似于:

In your case it would be something like:

MATCH (p1:Person), (p2:Person)
WITH p1, p2
WHERE rand() < 0.1
MERGE p1-[:LIKES]->p2

请小心一点，因为第一个MATCH指定了所有人与其他所有人的完整笛卡尔积，随着您的Person节点的增长，笛卡尔积可以快速增长.迈克尔在帖子的WITH上放置了LIMIT

Just be careful with that as the first MATCH specifies a full cartesian product of all people with all other people which can grow quickly as your Person nodes grow. Michael puts a LIMIT on his WITH in the post

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