Intro to GraphQL for Database Developers
- 2. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Intro to GraphQL for Database Developers Dan McGhan Developer Advocate @Oracle May 16, 2019
- 3. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Safe Harbor Statement The following is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, timing, and pricing of any features or functionality described for Oracle’s products may change and remains at the sole discretion of Oracle Corporation.
- 4. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | About me • Dan McGhan – Developer Advocate @Oracle – Focus on JavaScript and Oracle Database • Contact Info – [email protected] – @dmcghan – jsao.io 4
- 5. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Agenda Overview of GraphQL Type system and query language Demo 1 2 3 5
- 6. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Agenda Overview of GraphQL Type system and query language Demo 1 2 3 6
- 7. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | What is GraphQL? • A query language for APIs created by Facebook – Designed to make APIs more flexible and efficient • Consists of – Type system – Query language and execution semantics – Static validation – Type introspection
- 8. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | GraphQL history • Internal Facebook project since 2012 • First specification released publicly in 2015 – Regular updates since then • 2019: One of the hottest buzzwords in tech 8
- 9. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Spec vs. implementation • Facebook publishes a spec and a reference implementation – The spec describes how a GraphQL implementation should work – GraphQL.js is the reference implementation in JavaScript
- 10. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Primary benefits of GraphQL • Addresses under fetching – Can get many resources in a single request • Addresses over fetching – Can project only what’s needed for the app • Organization is based on types and fields rather than URL endpoints – GraphQL servers have a single “smart” endpoint • Evolve APIs without versions
- 11. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | REST vs GraphQL REST GraphQL Can send over HTTP Can send over HTTP Can return JSON Can return JSON Endpoint is the object identity Object identity is part of the query Resource is determined by the server Server declares what is available, client requests what it needs May require loading from multiple URLs Gets all the data in a single request GET or POST to same URL query{} and mutation{} use same URL Calls are stateless Query and mutation operations are stateless 11
- 12. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | 12 Web Browser Web Server Database SQL
- 13. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | 13 Web Browser Web Server Database SQLGraphQL
- 14. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Agenda Overview of GraphQL Type system and query language Demo 1 2 3 14
- 15. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Type system • Describes the objects that can be returned – Schema Definition Language expresses the GraphQL schema shape and types • Default scalar types – ID, Int, Float, String, Boolean • Other types – Object, Interface, Union, Enum, Input Object, List, Directive
- 16. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Operation types • Query – Think: SELECT or Data Query Language (DQL) • Mutation – Think: Data Manipulation Language (DMLP • Subscription – Think: Continuous Query Notification (CQN)
- 17. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Let’s start with something we know…
- 18. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | EMP and DEPT DDL
- 19. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | EMP and DEPT as GraphQL schema language
- 20. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Adding a root object
- 21. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Rolling the query root into a schema
- 22. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | REST request/response REST GET /departments/1 22 REST Response { "deptno": 1, "dname": "ACCOUNTING", "loc": "NEW YORK" }
- 23. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | GraphQL query/response GraphQL Query { department(id: 1) { deptno dname loc } } 23 Response { "data": { "department": { "deptno": 1, "dname": "ACCOUNTING", "loc": "NEW YORK" } } }
- 24. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | GraphQL query/response GraphQL Query 2 { department(id: 1) { deptno dname } } 24 Response 2 { "data": { "department": { "deptno": 1, "dname": "ACCOUNTING" } } }
- 25. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Agenda Overview of GraphQL Type system and query language Demo 1 2 3 25
- 26. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | 26 GraphQL Demo Technologies ‘GraphiQL’ UI express, express-graphql, graphql, and node-oracledb modules Oracle Database Queries and responses GraphQL requests over HTTP Persistence
- 27. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Closing thoughts • REST isn’t going away anytime soon – And it still has some advantages over GraphQL • But GraphQL is like giving SQL to front-end developers – We all know how powerful SQL is! • Keep GraphQL on your radar – Front-end devs will likely be asking for it soon…
- 28. Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | Where to go from here • https://graphql.org/ – The “home” for GraphQL; great learning material • https://www.howtographql.com – Another excellent learning resource with videos • https://graphql.github.io/graphql-spec/ – Specification • https://goodapi.co/blog/rest-vs-graphql – Fair, unbiased comparison of REST and GraphQL
Editor's Notes
- #9: Adoption has been rapid since first public spec released in 2015 Specification unlike REST. Spec is Royalty free - Open Web Foundation Agreement (OWFa) v1.0 Regular spec updates. Current is June 2018 and no longer a ‘Draft RFC’. Contains the Schema Definition Language GraphQL is used in other languages, but this talk is about Node.js I’ve grabbed a few logos of companies using GraphQL from the graphql.org site and other public sources. Oracle is included – I know of at least one product group inside Oracle seriously using GraphQL internally.
- #12: Gets all data....: Performance benefits from requiring a single request Stateless allows scaling via cloning of GraphQL server instances
- #23: To set the scene of where we’ve come from, let’s look at a REST example A GET call is made to our endpoint for resource 2 <Click> Typically most new APIs give a JSON response If you’ll forgive my nursery tune joke and accept that AGE is a string, in this example we get ‘Old MacDonald’ as the payload I promise no more bad jokes.
- #24: Let's look at GraphQL the 'graph query language'. Here we have a declarative query that is submitted, typically over HTTP This query with the root field ‘farmer' asks for the farmer with id of 2. Specifically it asks for the id, the name and the age of that farmer to be returned. <click> The GraphQL specification doesn’t say JSON has to be returned but in-line with REST usage, it typically is.
- #25: Let's look at GraphQL the 'graph query language'. Here we have a declarative query that is submitted, typically over HTTP This query with the root field ‘farmer' asks for the farmer with id of 2. Specifically it asks for the id, the name and the age of that farmer to be returned. <click> The GraphQL specification doesn’t say JSON has to be returned but in-line with REST usage, it typically is.
- #27: This is what the demo will do. We’ll make some GraphQL queries from a browser using the fantastic GraphiQL (pronounced Graphical) interface. These queries talk to our GraphQL server running in Node.js. The npm eco system has some excellent packages to work with GraphQL. Node.js uses Oracle’s open source node-oracledb module to query Oracle Database. In this particular example I’m using Oracle’s newish Document storage APIs “Simple Oracle Document Acces" or SODA. By default SODA documents are JSON, making it perfect for working with GraphQL (or REST for that matter). I’ll talk a bit more about SODA in a few slides. Note I could easily have used Oracle DB 12.1.0.2’s native JSON functionality, or even manually constructed JSON strings by using standard SQL.