带有Null的.json格式的Cypher查询

Question

我对neo4j还很陌生，我想编写一个读取.json格式的查询，并创建一个节点图。下面是我的查询，它在没有null属性的文件中成功，在json文件中有null属性时不成功。

代码：

CALL apoc.load.json("file:/graph-phase1-labelled.json") YIELD value  
UNWIND value.nodes as nodes
UNWIND nodes.properties as prop
MERGE(n1:Node{src:prop.sourceIP})

MERGE(n2:Node{dst:prop.destIP})  
WITH n1,n2,prop
MERGE (n1)-[:CONNECTED_TO]->(n2)
RETURN n1,n2,prop

错误：

Cannot merge the following node because of null property value for 'src': (:Node {src: null})

有人知道什么可以解决这个问题吗？

Answer 1

由于不能对null属性进行合并，因此必须筛选出其中包含null的行。示例：

CALL apoc.load.json("file:/graph-phase1-labelled.json") YIELD value
UNWIND value.nodes as nodes
UNWIND nodes.properties as prop
WHERE prop.sourceIP IS NOT NULL prop.destIP IS NOT NULL
WITH prop
MERGE(n1:Node{src:prop.sourceIP})
MERGE(n2:Node{dst:prop.destIP})
WITH n1,n2,prop
MERGE (n1)-[:CONNECTED_TO]->(n2)
RETURN n1,n2,prop

Answer 2

我已经通过以下查询解决了这个问题：

call apoc.load.json("file:/graph-phase1-labelled1.json") yield value
unwind value.nodes as nodes
unwind nodes.properties as prop 
with prop where prop.sourceIP is not null
with prop where prop.destIP is not null
merge(n1:Node{src:prop.sourceIP}) 
merge(n2:Node{dest:prop.destIP}) 
with prop,n1,n2
merge (n1)-[ :connected_to]->(n2)
return n1,n2,prop