# Cypher

- [[cypher relationships]]

A pattern matching query language made for graphs

- [[Declartive]]
- [[Expressive]]
- [[Pattern Matching]]

{{ https://i.imgur.com/u5vQ9Rm.jpg }}



### 연결이 없는 노드 조회

<code>
MATCH (b:Brand) WHERE NOT(b) - [] -> () RETURN b
</code>

### CREATE

<code>
CREATE (j:Person {name: 'Jennifer'}) RETURN j
</code>

### UPDATE

<code>
MATCH (p:Person {name: 'Jennifer'})
SET p.birthdate = date('1980-01-01')
</code>

### RELATION

<code>
CREATE (j:Person {name: 'Jennifer'})-[rel:IS_FRIENDS_WITH]->(m:Person {name: 'Mark'})
</code>

### MATCH

<code>
MATCH (b:Brand {name:"Chanel"}) RETURN b
</code>

<code>
MATCH (p:Person {name: 'Jennifer'}) RETURN p
</code>

### INDEXING

<code>
CREATE INDEX ON :Product(productName);
CREATE INDEX ON :Product(unitPrice);
</code>

### FILTER

<code>
MATCH (p:Product)
WHERE p.productName IN ['Chocolade','Chai']
RETURN p.productName, p.unitPrice;
</code>

### CONSTRAINT

<code>
CREATE CONSTRAINT ON (n:<LabelName>) ASSERT n.<propertyKey> IS UNIQUE
</code>

multiple column
<code>
CREATE CONSTRAINT ON (n:Person) ASSERT (n.firstname, n.surname) IS NODE KEY
</code>

제약 조회
<code>
SHOW CONSTRAINTS
</code>

{{ https://i.imgur.com/Sc1Hv3D.jpg }}

### DELETE

<code>
MATCH (n:Person {name: 'UNKNOWN'})
DELETE n
</code>

### Delete all nodes and relationships

<code>
MATCH (n)
DETACH DELETE n
</code>

### Delete a node with all its relationships

<code>
MATCH (n {name: 'Andy'})
DETACH DELETE n
</code>

## Docs

- [[Cypher Query]]
- [[Extend Cypher]]
- [[Graph Model]]