在不复制现有关系的情况下更新 neo4j 关系属性

Question

我有以下内容来首先创建节点之间的关系（在上一步中已经创建的节点）

MATCH (a:node), (b:node) WHERE a.name = 'sw1' AND b.name = 'sw2'
             merge (a)-[c:connect {packets_transmitted:0,packets_recieved:0}]->(b)

我需要更新属性而不复制已经存在的关系。现在每当我运行密码时，节点之间的关系 connect 就会重复。我该怎么办？

这是我用来更新关系属性的内容：

MATCH (a:node),(b:node) where a.name='sw1' and b.name ='sw2'
      merge (a)-[c:connect]->(b)
      set c.packets_transmitted = 250,c.packets_recieved = 300

更新： 这是我在 python 中编写的完整代码（我将其修改为尽可能清晰，但仍然存在重复关系）

注意：我直接在neo4j中执行，代码运行正常

cqlCreate_1=f"merge(n:node{{name:'openflow:2'}})"
with graphDB_Driver.session() as graphDB_Session:
        graphDB_Session.run(cqlCreate_1)

cqlCreate_3=f"merge(m:node{{name:'2e:38:64:0e:e8:1f'}})"
with graphDB_Driver.session() as graphDB_Session:
        graphDB_Session.run(cqlCreate_3)

cqlCreate_2=f"MATCH (a:node),(b:node) WHERE a.name ='openflow:2'\
and b.name='2e:38:64:0e:e8:1f'\
merge (a)-[c:connect{{p:0}}]-(b)"
with graphDB_Driver.session() as graphDB_Session:
        graphDB_Session.run(cqlCreate_2)

cqlUpdate=f"MATCH (a:node)-[c:connect]-(b:node) where a.name='openflow:2'\
and b.name='2e:38:64:0e:e8:1f'\
set c.p=200"
with graphDB_Driver.session() as graphDB_Session:
    graphDB_Session.run(cqlUpdate)

Answer 1

如果你想在节点之间找到一个 :connect 关系（你不关心匹配的属性是什么）然后更新属性，那么只 MERGE 关系，不要包含属性图案。然后使用 SET 将属性设置为新值：

MATCH (a:node), (b:node) 
WHERE a.name = 'sw1' AND b.name = 'sw2'
MERGE (a)-[r:connect]-(b)
SET r.packets_transmitted = 0, r.packets_recieved = 0

如果只应在创建时设置属性，则改为使用 ON CREATE SET。

编辑：我删除了 MERGE 模式中的方向，这将允许它合并到节点之间现有的 :connect 关系，无论方向如何。

Answer 2

答案：创建关系时不需要建立关系属性，因为每次都执行整个代码，这会导致关系重复。下面是更正后的代码：

    cqlCreate_1=f"merge(n:node{{name:'openflow:2'}})"
with graphDB_Driver.session() as graphDB_Session:
        graphDB_Session.run(cqlCreate_1)

cqlCreate_3=f"merge(m:node{{name:'2e:38:64:0e:e8:1f'}})"
with graphDB_Driver.session() as graphDB_Session:
        graphDB_Session.run(cqlCreate_3)

cqlCreate_2=f"MATCH (a:node),(b:node) WHERE a.name ='openflow:2'\
and b.name='2e:38:64:0e:e8:1f'\
merge **(a)-[c:connect]-(b)**"
with graphDB_Driver.session() as graphDB_Session:
        graphDB_Session.run(cqlCreate_2)

cqlUpdate=f"MATCH (a:node)-[c:connect]-(b:node) where a.name='openflow:2'\
and b.name='2e:38:64:0e:e8:1f'\
set c.p=200"
with graphDB_Driver.session() as graphDB_Session:
    graphDB_Session.run(cqlUpdate)

在不复制现有关系的情况下更新 neo4j 关系属性

Updating neo4j relationship properties without duplicating the existing relationship

relationship

neo4j