[Neo4j] Cypher Query 기본 문법 및 예제

01. 기본 문법

 

Basic return

MATCH (n)
RETURN n

 

 

 

Create a simple node with properties

CREATE (:NodeName  {name: "James Dean", age: 24})

 

 

 

Update return with column names

MATCH (n)
RETURN n.name AS Name, n.age AS Age

 

 

 

Delete all element in the database(delete all nodes and edges)

MATCH (n)
DETACH DELETE n

 

 

 

 

 

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02. 예제 #1

 

Two nodes and relationship between User id 0 is interested in the item id 0

CREATE (a:Users {userId: 0})
CREATE (b:Items {itemId: 0})
CREATE (a)-[:IS_INTERESTED_IN]->(b)

 

 

 

Check it labels

call db.labels()

 

 

Check it relationship

call db.relationshipTypes

 

 

 

 

 

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03. 예제 #2

 

Connect nodes

MATCH (a:Users {userId: 0})      
CREATE (b:Items {itemId: 1})
CREATE (a)-[:HAS_PURCHASED]->(b)

 

 

 

Create more nodes

CREATE (u2:Users {userId: 2}),
       (u3:Users {userId: 3}),
       (u4:Users {userId: 4})

 

 

 

Connect nodes

MATCH (a:Users {userId: 0}), (u2:Users {userId: 2})
CREATE (a)-[:HAS_INTRODUCED_THEITEM_TO]->(u2)      
WITH a                                             

MATCH (a), (u3:Users {userId: 3})                  
CREATE (a)-[:HAS_INTRODUCED_THEITEM_TO]->(u3)
WITH a                                             

MATCH (a), (u4:Users {userId: 4})                  
CREATE (a)-[:HAS_INTRODUCED_THEITEM_TO]->(u4)

 

 

 

Check it

MATCH (n) 
RETURN n

 

 

 

Check it relationship

call db.relationshipTypes

 

 

 

Delete all nodes and edge

MATCH (n)
DETACH DELETE n

 

 

 

 

 

 

---

 

 

04. 예제 #3

 

Merge either matches existing nodes

MERGE (u0:Users {userId: 0})
MERGE (u1:Users {userId: 1})
MERGE (u2:Users {userId: 2})
MERGE (u3:Users {userId: 3})
MERGE (u4:Users {userId: 4})

MERGE (i0:Items {itemId: 0})
MERGE (i1:Items {itemId: 1})
WITH u0, u1, u2, u3, u4, i0, i1                               

MATCH (a:Users {userId: 0}), (i0:Items {itemId: 0})
MERGE (a)-[:IS_INTERESTED_IN]->(i0)
WITH a, u1, u2, u3, u4, i1                                      

MATCH (a), (i1:Items {itemId: 1})
MERGE (a)-[:HAS_PURCHASED]->(i1)
WITH a, u2, u3, u4                                              

MATCH (a), (u2:Users {userId: 2})
MERGE (a)-[:HAS_INTRODUCED_THEITEM_TO]->(u2)
WITH a, u3, u4                                                  

MATCH (a), (u3:Users {userId: 3})
MERGE (a)-[:HAS_INTRODUCED_THEITEM_TO]->(u3)                    
WITH a, u4                                                     

MATCH (a), (u4:Users {userId: 4})
MERGE (a)-[:HAS_INTRODUCED_THEITEM_TO]->(u4)

 

 

 

Check it

MATCH (n)
RETURN n

 

 

 

 

 

---

 

 

05. 예제 #4

 

Update one property

MATCH (n {userId: 0})
SET n.name = "James Dean"
RETURN n

 

 

 

Update all properties

MATCH (n {itemId: 0})
SET n = {name: "Porsche Super Speedster 23F", Engine: "1.5 L Type 528/2 B4"}
RETURN n

 

 

 

 

Delete edge property

MATCH (n {itemId: 0})
SET n.Engine = NULL
RETURN n

 

no change