Neo4J 和 Cypher 查詢

Question

我是 Neo4j 和 Cypher 查詢的新手。我的創建查詢就像每個商店有 2 個冷水機，每個冷水機有 2 個 PLC，每個冷水機有 2 個傳感器。

創建如下

Create(:SHOP{name:"Shop1"})-[:hasChiller]->(:CHILLER{name:"Chiller1"})
Create(:SHOP{name:"Shop1"})-[:hasChiller]->(:CHILLER{name:"Chiller2"})

Create(:SHOP{name:"Shop2"})-[:hasChiller]->(:CHILLER{name:"Chiller3"})
Create(:SHOP{name:"Shop2"})-[:hasChiller]->(:CHILLER{name:"Chiller4"})

Create(:CHILLER{name:"Chiller1"})-[:hasPLC]->(:PLC{name:"Plc1"})
Create(:CHILLER{name:"Chiller1"})-[:hasPLC]->(:PLC{name:"Plc2"})

Create(:CHILLER{name:"Chiller2"})-[:hasPLC]->(:PLC{name:"Plc3"})
Create(:CHILLER{name:"Chiller2"})-[:hasPLC]->(:PLC{name:"Plc4"})

Create(:CHILLER{name:"Chiller3"})-[:hasPLC]->(:PLC{name:"Plc5"})
Create(:CHILLER{name:"Chiller3"})-[:hasPLC]->(:PLC{name:"Plc6"})

Create(:CHILLER{name:"Chiller4"})-[:hasPLC]->(:PLC{name:"Plc7"})
Create(:CHILLER{name:"Chiller4"})-[:hasPLC]->(:PLC{name:"Plc8"})

Create(:PLC{name:"Plc1"})-[:hasSensor]->(:SENSOR{name:"Sensor1"})
Create(:PLC{name:"Plc1"})-[:hasSensor]->(:SENSOR{name:"Sensor2"})
Create(:PLC{name:"Plc2"})-[:hasSensor]->(:SENSOR{name:"Sensor3"})
Create(:PLC{name:"Plc2"})-[:hasSensor]->(:SENSOR{name:"Sensor4"})
Create(:PLC{name:"Plc3"})-[:hasSensor]->(:SENSOR{name:"Sensor5"})
Create(:PLC{name:"Plc3"})-[:hasSensor]->(:SENSOR{name:"Sensor6"})
Create(:PLC{name:"Plc4"})-[:hasSensor]->(:SENSOR{name:"Sensor7"})
Create(:PLC{name:"Plc4"})-[:hasSensor]->(:SENSOR{name:"Sensor8"})
Create(:PLC{name:"Plc5"})-[:hasSensor]->(:SENSOR{name:"Sensor9"})
Create(:PLC{name:"Plc5"})-[:hasSensor]->(:SENSOR{name:"Sensor10"})
Create(:PLC{name:"Plc6"})-[:hasSensor]->(:SENSOR{name:"Sensor11"})
Create(:PLC{name:"Plc6"})-[:hasSensor]->(:SENSOR{name:"Sensor12"})
Create(:PLC{name:"Plc7"})-[:hasSensor]->(:SENSOR{name:"Sensor13"})
Create(:PLC{name:"Plc7"})-[:hasSensor]->(:SENSOR{name:"Sensor14"})
Create(:PLC{name:"Plc8"})-[:hasSensor]->(:SENSOR{name:"Sensor15"})
Create(:PLC{name:"Plc8"})-[:hasSensor]->(:SENSOR{name:"Sensor16"})

然而，在 SHOP1 下獲得傳感器的匹配

MATCH(s:SHOP{name:"Shop1"})-[:hasChiller]->(cc:CHILLER)-[:hasPLC]->(pp:PLC)-[:hasSensor]->(ss:SENSOR) return ss.name

什么都不返回。說沒有變化，也沒有數據。

我正在 Neo4J 沙盒環境中嘗試這個。我這樣做是基於我在 SQL SERVER GRAPH 2019 中使用 match 子句的理解。

誰能指出我哪里出錯了？

Answer 1

您不正確地創建了“相同”節點的多個實例。 您應該創建每個節點一次，然后在需要創建涉及該節點的關系時使用其綁定的變量名稱。

刪除所有數據並改為遵循此模式（您必須填寫“...”部分）：

CREATE
  (sh1:SHOP{name:"Shop1"}), (sh2:SHOP{name:"Shop1"}),
  (c1:CHILLER{name:"Chiller1"}), (c2:CHILLER{name:"Chiller2"}),(c3:CHILLER{name:"Chiller3"}), (c4:CHILLER{name:"Chiller4"}),
  (p1:PLC{name:"Plc1"}), ..., (p8:PLC{name:"Plc8"}),
  (se1:SENSOR{name:"Sensor1"}), ..., (se16:SENSOR{name:"Sensor16"}),

  (sh1)-[:hasChiller]->(c1), (sh1)-[:hasChiller]->(c2),
  ... // create remaining relationships using bound variable names for nodes