我如何避免在neo4j中多次访问具有相同属性的节点

Question

我的Cypher查询：

MATCH p =(o:Order)-[r:seeks*2..8]->(o:Order)
WHERE o.Name="000093" AND ALL(x IN tail(nodes(p)) WHERE SINGLE(y IN    tail(nodes(p)) WHERE x=y))
RETURN extract(n IN nodes(p)| n.Name) AS OrderID, extract(u IN nodes(p)| u.UserName) AS UserName,length(p), endNode(r[0])
ORDER BY length(p)

我想避免在路径中具有相同属性值的节点，如何避免它们？

["000093","000090","000096","000097","000107","000091","000089","000093"]
["yunis","gio","Anhar","Jhon","**shakilbit**","xalima","**shakilbit**","yunis"]

因此，0000107和000089的订单是由同一用户名Shakilbit放置的，我有什么办法避免在同一条路径上将这些订单放在同一条路径上，谢谢！neo4j ..据我所知，社区非常有帮助。

Answer 1

使用APOC过程，您可能需要将收藏作为集合（消除重复值的情况）并比较大小。如果存在重复项，则集合的大小将较小。

MATCH p =(o:Order)-[r:seeks*2..8]->(o:Order)
WHERE o.Name="000093" AND ALL(x IN tail(nodes(p)) WHERE SINGLE(y IN    tail(nodes(p)) WHERE x=y))
WITH p, o, r, extract(u IN nodes(p)| u.UserName) AS UserName
// need to make some adjustments since first and last nodes are same
WHERE size(UserName) - 1 = size(apoc.coll.toSet(tail(UserName)))
RETURN extract(n IN nodes(p)| n.Name) AS OrderID, UserName, length(p), endNode(r[0])
ORDER BY length(p)

替代方案是重复您的ALL(x in tail...) WHERE single()...谓词，但在用户名集合中（或在您现有的All（）谓词中包含此检查，尽管这可能很昂贵）。您可能需要介绍每个人，看看哪个更具性能。