Neo4j仅在唯一时加载CSV [英] Neo4j Load CSV only when unique

问题描述

如果我的csv如下:

"route_id","service_id","trip_id","trip_headsign"
4973_3, 2, 14519396, "Bf. Tostedt"
4973_3, 2, 14519395, "Bf. Tostedt"
4973_3, 1, 14519379, "Sittensen, Schule"
4973_3, 1, 14519391, "Sittensen, Bahnhofstraße"
4973_3, 2, 14519394, "Bf. Tostedt"
4973_3, 1, 14519390, "Bf. Tostedt"
4973_3, 3, 14519381, "Bf. Tostedt"
4973_3, 4, 14519392, "Bf. Tostedt"

，并且我只想在trip_headsign是唯一时加载，因此在上述情况下，我只会创建Trip 3次.我该怎么办?

and I want to load only when trip_headsign is unique, so in above case I would only create Trip 3 times. How do i do it?

我到目前为止如下:

load csv with headers from  
 'file:///hamburg/trips.txt' as csv   
 create (t:Trip {id: csv.trip_id, service_id: csv.service_id, headsign: csv.trip_headsign}); 

但我收到此错误:

Node(76020) already exists with label `Trip` and property `headsign` = 'Bf. Tostedt'

我有意将首字母签名作为唯一约束，因为我只希望每个签名仅存在一次.

I have intentionally keps headsign as unique constraint because I only want everyone of it to exist only once.

推荐答案

我现在想通了.谢谢

load csv with headers from  
'file:///hamburg/trips.txt' as csv   
merge (t:Trip {headsign: csv.trip_headsign})
on match set t.id =  csv.trip_id
on match set t.service_id = csv.service_id

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