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# GraphQL Cheatsheet

## Overview of unique features

- Query language for APIs
- Allows clients to specify exactly what data they need
- Supports introspection and self-documentation
- Can be used for building efficient and flexible APIs

## Querying

Query for a specific field

{

user(id: "123") {

name

email

}

}

Query for a specific field with an alias

{

john: user(id: "123") {

name

}

jane: user(id: "456") {

name

}

}

Query for a field with arguments

{

users(role: "admin") {

name

}

}

Query for a field with nested objects

{

user(id: "123") {

name

posts {

title

content

}

}

}

## Mutations

Create a new user

mutation {

createUser(input: {name: "John", email: "john@example.com"}) {

id

name

email

}

}

Update an existing user

mutation {

updateUser(id: "123", input: {name: "John Doe"}) {

id

name

email

}

}

Delete a user

mutation {

deleteUser(id: "123") {

id

name

email

}

}

## Fragments

Define a fragment

fragment UserInfo on User {

name

email

}

Use a fragment in a query

{

user(id: "123") {

...UserInfo

}

}

Define a fragment with variables

# Define a fragment with variables
fragment UserInfo on User {
  name
  email
  posts(first: $count) {
    title
    content
  }
}

# Use a fragment with variables
query($count: Int!) {
  user(id: "123") {
    ...UserInfo
  }
}

Directives

# Use a directive to conditionally include a field
{
  user(id: "123") {
    name
    email
    posts @include(if: $withPosts) {
      title
      content
    }
  }
}

Schema

# Define a schema
type User {
  id: ID!
  name: String!
  email: String!
  posts: [Post!]!
}

type Post {
  id: ID!
  title: String!
  content: String!
  author: User!
}

type Query {
  user(id: ID!): User
  posts: [Post!]!
}

type Mutation {
  createUser(input: CreateUserInput!): User!
  updateUser(id: ID!, input: UpdateUserInput!): User!
  deleteUser(id: ID!): User!
}

input CreateUserInput {
  name: String!
  email: String!
}

input UpdateUserInput {
  name: String
  email: String
}

Resources

- [GraphQL documentation](https://graphql.org/learn/)

- [GraphQL tutorial](https://www.tutorialspoint.com/graphql/index.htm)

- [GraphQL forum](https://stackoverflow.com/questions/tagged/graphql) for community support and troubleshooting.