Schema

A schema defines the capabilities of a GraphQL server. Much like a database schema, it describes the structure and the types your API can return.

Types

Types are the primary building blocks of a GraphQL schema. They define the capabilities of your API and the kind of data you can get from it.

type User {
  id: ID!
  name: String!
  email: String!
  created_at: String!
  updated_at: String
}

The Root Types

There can be up to 3 special root types in a GraphQL schema. They define the root fields that a query may have. While they are all Object Types, they differ in functionality.

Query

Every GraphQL schema must have a Query type which contains the queries your API offers. Think of queries as REST resources which can take arguments and return a fixed result.

type Query {
  me: User
  users: [User!]!
  userById(id: ID): User 
}

Mutation

In contrast to the Query type, the fields of the Mutation type are allowed to change data on the server.

type Mutation {
  createUser(name: String!, email: String!, password: String!): User
  updateUser(id: ID, email: String, password: String): User
  deleteUser(id: ID): User
}

Subscription

Rather than providing a single response, the fields of the Subscription type return a stream of responses, with real-time updates.

type Subscription {
  newUser: User
}