About
This article is about the schema (type) definition of GraphQL.
The implementation graphql/type module is the engine for defining GraphQL types and schema.
Example
The below type is a shorthand notation. The API is more expressive and allows types and fields to be documented. See the getting started schema starWarsSchema.js
- an enum
enum Episode { NEWHOPE, EMPIRE, JEDI }
- an interface
interface Character {
id: String! // ! means not null
name: String
friends: [Character]
appearsIn: [Episode]
}
- types implementing ther interface
type Human implements Character {
id: String
name: String
friends: [Character]
appearsIn: [Episode]
homePlanet: String
}
type Droid implements Character {
id: String
name: String
friends: [Character]
appearsIn: [Episode]
primaryFunction: String
}
- The Entry point that defines the whole schema (by default, the name is Query)
type Query {
hero(episode: Episode): Character
human(id: String!): Human
droid(id: String!): Droid
}
Built-in
- String, Boolean - Are built-in scalars that the type system provided.
- __Schema, __Type, __TypeKind, __Field, __InputValue, __EnumValue, __Directive preceded with a double underscore, indicating that they are part of the introspection system.