GraphQL is a query language for your API, and a server-side runtime for executing queries by using a type system you define for your data.

1. Presented By:
Addi
Software Consultant
Introduction to
GraphQL

2. Lack of etiquette and manners is a huge turn off.
KnolX Etiquettes
Punctuality
Respect Knolx session timings, you
are requested not to join sessions
after a 5 minutes threshold post
the session start time.
Feedback
Make sure to submit a constructive
feedback for all sessions as it is
very helpful for the presenter.
Silent Mode
Please keep your screen on mute,
until it's necessary
Avoid Distraction
Be along with the presenter during
the session and enjoy.

3. Agenda
● Introduction to GraphQL
● Advantages over REST
● Schema
● Data Fetchers
●
● Demo

4. What is GraphQL?
● GraphQL is a query language for your API .
● “QL” stands for Query Language.
● GraphQL was developed internally by Facebook in 2012 before being
publicly released in 2015.

6. Disadvantages over REST
● Using Graphql in simple application is hectic.
● When we needs to query asking for a lot of fields and resources.
● schemas are static and the response the clients are going to get
depends on the schema definition and the query they make.

7. GraphQL Schema
● GraphQL API has a schema that defines each field that can be
queried(i.e, “payload”).
● It is not JSON (even though it looks deliberately similar), it is a GraphQL
schema.
● It defines each field that can be queried or mutated and what types
those fields are.

8. GraphQL Schema
type Query {
songById(id: ID): Song
}
type Song {
id: ID
name: String
genre: String
artist: Artist
}
type Artist {
id: ID
firstName: String
lastName: String
}

9. GraphQL Datafetchers
● Data Fetcher is probably the most important concept for a GraphQL.
● A Data Fetcher is used to fetch data when it is executed in query. And
whenever a query is executed GraphQL calls appropriate DataFetcher
to get the data.
● It is an interface with a single method, taking a single argument of
type.

10. Important Topics
● Graphql-java
● Db connection
● Runtime wiring

11. DEMO

12. Q/A

13. References
● https://www.graphql-java.com/documentation/v15/
● https://graphql.org/learn/
● https://graphql.org/code/#java

14. Thank You !