Querying Graphs with GraphQL

neo4j.com/developer

Property Graph Model

CAR

name: “Dan”born: May 29, 1970

twitter: “@dan”name: “Ann”

born: Dec 5, 1975

since: Jan 10, 2011

brand: “Volvo”model: “V70”

LOVES

LOVES

LIVES WITHPERSON PERSON

Whiteboard Model Is the Physical Model

Cypher: Powerful & Expressive Graph Query Language

MATCH (:Person { name:“Dan”} ) -[:LOVES]-> (:Person { name:“Ann”} )

LOVES

Dan Ann

LABEL PROPERTY

NODE NODE

LABEL PROPERTY

Use Neo4j like a regularbacking database

https://launchpad.graphql.com/3wzp7qnjv

Or ... turn Neo4j intoa native GraphQL backend

1. take GraphQL query2. transform to Cypher3. execute against graph4. return results

Based on ... what?Schema!

Which schema?

Neo4j is schema-free, so:

[x] Use GraphQL Schema

Neo4j isopen source& extensible

Let‘s build an extension

How hard can it be?

Transform + projectQuery / Results

Thank you!

Introducing:

neo4j-graphql

What‘s in the box?

Basics

Endpoint with basic authhost:port/graphqlPOST schema file

run queries with paramsproject results

Cool Features

generate & run single graph queryauto generated mutations for types

first, offset, orderBy, @relationlookup by any field

fragments, unlimited nesting

Power Up: @cypher

computed fieldscustom mutations & queries

parameter support

Cool! How can I use it?

npm install -g neo4j-graphql-cli

neo4j-graphql [my.schema]

movies.schema

add superpower

type Actor {totalMovies:Int @cypher(statement:"RETURN size( (this)-[:ACTED_IN]->(:Movie) ) as total")...

type Movie {similar:[Movie] @cypher(statement:"MATCH (this)-->(:Genre)<--(o:Movie) RETURN o LIMIT 10")...

type QueryType {topRatedMovies(score:Int) [Movie] @cypher(statement:"MATCH (m:Movie)<-[r:RATED]-(:User) WHERE r.score > $score RETURN m, avg(r.score) as scoreORDER BY score DESC LIMIT 10")

github.com/neo4j-graphql

graphql.communitygraph.org