Cypher Query Language

Chicago Graph Database Meet-UpMax De Marzi

What is Cypher?

•Graph Query Language for Neo4j

•Aims to make querying simple

Design Decisions

Pattern matching

AA

BB CC

Design Decisions

Pattern matching

Design Decisions

Pattern matching

Design Decisions

Pattern matching

Design Decisions

Pattern matching

Design Decisions

ASCII-art patterns

() --> ()

Design Decisions

Directed relationship

(A) --> (B)

AA BB

Design Decisions

Undirected relationship

(A) -- (B)

AA BB

Design Decisions

specific relationships

A -[:LOVES]-> B

AA BBLOVES

Design Decisions

Joined paths

A --> B --> C

AA BB CC

Design Decisions

multiple paths

A --> B --> C, A --> C

AA

BB CC

A --> B --> C <-- A

Design Decisions

Optional relationships

A -[?]-> B

AA BB

Mutating CypherNew in Neo4j 1.8

Create Nodes

The Ninja Turtles

CypherCREATE turtle1 = {name : 'Donatello'}, turtle2 = {name : ‘Michelangelo'}, turtle3 = {name : ‘Raphael'}, turtle4 = {name : ‘Leonardo'}

Create Relationships

The Ninja Turtles are disciples of

Splinter

Cypher

START t1 = node(1), t2 = node(2), t3 = node(3), t4 = node(4)CREATE s = {name: ‘Splinter’ }, t1-[r:DISCIPLE]->s, t2-[r:DISCIPLE]->s, t3-[r:DISCIPLE]->s, t4-[r:DISCIPLE]->s

Delete Nodes

Shredder is defeated

CypherSTART  s = node:nodes(name = ‘Shredder’)DELETE s

Update Properties

Donatello uses the Bo StaffMichelangelo is always hungry

CypherSTART t1 = node(0), t2 = node(2)SET t1.weapon = ‘Bo Staff’, t2.hungry = ‘Yes’

Delete Properties

Michelangelo nom nom nom

CypherSTART t2 = node(2)DELETE t2.hungry

Using Relate

The Ninja Turtles love pizza

A pizza node and 4 relationships

are created

CypherSTART turtles = node(1,2,3,4)RELATE turtles-[r:LOVE]->pizza

Using Relate again

The Ninja Turtles love pizza

A pizza node with name “Supreme”

and 4 relationships are created

CypherSTART turtles = node(1,2,3,4)RELATE turtles-[r:LOVE]-(pizza {name:’Supreme’})

Questions?

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